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All questions of CBT I for Civil Engineering (CE) Exam

There are total 10 students whose marks in an exam are 45, 65, 56, (P + 16), (2P + 3), 78, 24, (4P - 8), 44 and 48 respectively and mean marks of first 5 students is 49, then what is mean marks of last 5 students?
  • a)
    72.2
  • b)
    48.2 
  • c)
    64.2
  • d)
    72.2
Correct answer is option 'B'. Can you explain this answer?

Prasad Chaudhary answered
Calculating the Mean Marks of Last 5 Students
To calculate the mean marks of the last 5 students, we need to first find the total marks obtained by all 10 students and then subtract the total marks of the first 5 students from it.

Finding the Total Marks of All 10 Students
Given marks of the students are:
45, 65, 56, (P + 16), (2P + 3), 78, 24, (4P - 8), 44, 48
Sum of all these marks = 45 + 65 + 56 + (P + 16) + (2P + 3) + 78 + 24 + (4P - 8) + 44 + 48
Sum = 315 + 7P + 55

Finding the Total Marks of First 5 Students
Given mean marks of first 5 students = 49
Total marks of first 5 students = 5 * 49 = 245

Calculating the Mean Marks of Last 5 Students
Total marks of all 10 students = 315 + 7P + 55
Total marks of last 5 students = Total marks of all 10 students - Total marks of first 5 students
Total marks of last 5 students = 315 + 7P + 55 - 245
Total marks of last 5 students = 70 + 7P
Mean marks of last 5 students = Total marks of last 5 students / 5 = (70 + 7P) / 5 = 14 + 1.4P
Therefore, the mean marks of the last 5 students is 14 + 1.4P. Since no specific value of P is given in the question, we cannot determine the exact mean marks. So, the answer is not specified in the options provided.
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If cosec θ = x + 1/4x, then the value of cosec θ + cot θ is:
  • a)
    -2x
  • b)
    2x
  • c)
    1/2x
  • d)
    −1/2x
Correct answer is option 'B'. Can you explain this answer?

Shubham Sharma answered
Let cosec θ + cot θ = k
⇒ cosec θ - cot θ = 1/k
On adding, we get
2 cosec θ = k + 1/k = 2(x + 1/4x) = k + 1/k
⇒ x + 1/2x = k + 1/k ⇒ k = 2x

At present, the sum of ages of R and K is 63 years. The ratio of their ages after 7 years will be 7: 4 , what is the present age of R?
  • a)
    40 years
  • b)
    42 years
  • c)
    29 years
  • d)
    34 years
Correct answer is option 'B'. Can you explain this answer?

Tejas Verma answered
Let the present age of R is x
⇒ present age of K is 63 - x
7 years later
R's age = x + 7
K's age = 63 - x + 7= 70 - x
⇒ (x + 7) / (70 - x) = 7 / 4
⇒ 4x + 28= 490 - 7x
⇒ 11x = 462
⇒ x = 42 years
therefore present age of R = 42 years

In a certain code language, 315 means 'play is fun', 324 means 'game is nice', 614 means 'fun and nice'. Find the code for 'and'.
  • a)
    6
  • b)
    7
  • c)
    9
  • d)
    4
Correct answer is option 'A'. Can you explain this answer?

Raj Chauhan answered
To find the code for 'and', we need to analyze the given codes and identify the common pattern. Let's break down the given codes and look for any similarities:

Code 315: 'play is fun'
Code 324: 'game is nice'
Code 614: 'fun and nice'

Observations:
- The common word in all three codes is 'is', so it is likely represented by a common code.
- The common code in the first two codes is 3, and in the third code, it is 1.
- The common code in the second and third codes is 4, and in the first code, it is 5.
- The common code in the first and third codes is 1, and in the second code, it is 2.

Based on the above observations, we can conclude that each digit in the code represents a specific word. Let's assign the codes to the corresponding words:

3 -> 'is'
1 -> 'and'
5 -> 'play'
2 -> 'game'
4 -> 'nice'
6 -> 'fun'

Therefore, the code for 'and' is 1. Thus, the correct option is A) 6.

In an election contested by two candidates, a candidate who got 54% of the total votes won by a margin of 288 votes. Total votes are.
  • a)
    3000
  • b)
    3600
  • c)
    4000
  • d)
    4800
Correct answer is option 'B'. Can you explain this answer?

Kritika Sen answered
Given:
- The election is contested by two candidates.
- One candidate got 54% of the total votes.
- The winning candidate won by a margin of 288 votes.

To Find:
- The total number of votes.

Solution:
Let's assume the total number of votes as 'x'.

Step 1: Calculate the number of votes received by the winning candidate.
- The winning candidate received 54% of the total votes.
- So, the number of votes received by the winning candidate = (54/100) * x.

Step 2: Calculate the number of votes received by the losing candidate.
- The losing candidate received the remaining votes.
- So, the number of votes received by the losing candidate = x - (54/100) * x = (46/100) * x.

Step 3: Calculate the margin of victory.
- The winning candidate won by a margin of 288 votes.
- The margin of victory = (54/100) * x - (46/100) * x = 288.

Step 4: Solve the equation to find the value of 'x'.
- (54/100) * x - (46/100) * x = 288.
- (8/100) * x = 288.
- x = (288 * 100) / 8.
- x = 3600.

Therefore, the total number of votes is 3600.
Hence, option B is the correct answer.

In the following question, select the odd number pair from the given alternatives.
  • a)
    14 : 27
  • b)
    2 : 5
  • c)
    4 : 9
  • d)
    12 : 25
Correct answer is option 'A'. Can you explain this answer?

Hiral Menon answered
Odd Number Pair

To determine the odd number pair from the given alternatives, let's analyze each option:

Option A: 14 : 27
- 14 is an even number.
- 27 is an odd number.
- Therefore, this pair is an odd number pair.

Option B: 2 : 5
- Both 2 and 5 are odd numbers.
- Therefore, this pair is not an odd number pair.

Option C: 4 : 9
- Both 4 and 9 are odd numbers.
- Therefore, this pair is not an odd number pair.

Option D: 12 : 25
- 12 is an even number.
- 25 is an odd number.
- Therefore, this pair is an odd number pair.

Conclusion:
Among the given options, option A (14 : 27) is the odd number pair. The other options consist of either both even numbers or both odd numbers, making them not odd number pairs.

If an object is placed at between F and 2F in front of a Convex Lens, then the image formed will be
  • a)
    Beyond 2F
  • b)
    Diminished
  • c)
    Both of them
  • d)
    None of these
Correct answer is option 'A'. Can you explain this answer?

Jithin Chavan answered
When an object is placed between the focal point (F) and twice the focal length (2F) in front of a convex lens, the image formed will be beyond 2F. This can be explained using the concepts of ray diagrams and the characteristics of convex lenses.

Ray Diagram:
A ray diagram can be used to determine the position and characteristics of the image formed by a convex lens. In this case, we will draw three rays: one parallel to the principal axis, one passing through the center of the lens, and one passing through the focal point.

Characteristics of Convex Lenses:
1. Parallel rays of light converge after passing through a convex lens.
2. Rays passing through the center of the lens continue in a straight line without any deviation.
3. Rays passing through the focal point on one side of the lens emerge parallel to the principal axis on the other side.

Explanation:
1. Draw a horizontal line representing the principal axis of the lens.
2. Mark the focal point (F) on the principal axis, which is half the distance of the lens's focal length.
3. Place the object between F and 2F on the principal axis.
4. Draw a ray from the top of the object parallel to the principal axis. This ray will pass through the lens and converge at a point on the other side of the lens.
5. Draw a ray from the top of the object through the center of the lens. This ray will continue in a straight line without any deviation.
6. Draw a ray from the top of the object towards the focal point on the same side of the lens. This ray will emerge parallel to the principal axis on the other side of the lens.
7. The point where the rays intersect after passing through the lens is the position of the image.
8. In this case, the converging ray and the parallel ray intersect beyond 2F, indicating that the image is formed beyond 2F.

Therefore, the correct answer is option 'A' - the image formed will be beyond 2F.

If ab = 25, then the minimum value of a + b is:
  • a)
    10
  • b)
    8
  • c)
    24
  • d)
    16
Correct answer is option 'A'. Can you explain this answer?

Shubham Sharma answered
Minimum value of (a + b) can be obtained when a = b
Then a + b = 5 + 5 (∴ ab = 25 and a = b)
= 10

In one revolution, the object travels______ distance.
  • a)
    2πr
  • b)
    3πr
  • c)
    4πr
  • d)
    πr
Correct answer is option 'A'. Can you explain this answer?

Tejas Verma answered
In one revolution, the object travels 2πr distance. Revolution means a circular motion around an axis located outside the object. E.g., Rounding a curve in a car, merry go round, etc.

A man sells two scooters for Rs.12000 each. He makes a profit of 20% on one and a loss of 20% on the other. The profit/loss, on the whole, is
  • a)
    Rs.1000 profit
  • b)
    Rs.1000 loss
  • c)
    Rs.960 profit
  • d)
    Rs.960 loss
Correct answer is option 'B'. Can you explain this answer?

Mayank Mukherjee answered
Calculation of Profit/Loss on the Sale of Two Scooters

Given:
- Selling price of each scooter: Rs.12000
- Profit on one scooter: 20%
- Loss on the other scooter: 20%

Calculation:
1. Profit on the first scooter:
- Cost price of the first scooter = Rs.12000
- Profit = 20% of Rs.12000 = Rs.2400
- Selling price of the first scooter = Rs.12000 + Rs.2400 = Rs.14400
2. Loss on the second scooter:
- Cost price of the second scooter = Rs.12000
- Loss = 20% of Rs.12000 = Rs.2400
- Selling price of the second scooter = Rs.12000 - Rs.2400 = Rs.9600

Overall Profit/Loss:
- Total selling price = Rs.14400 + Rs.9600 = Rs.24000
- Total cost price = Rs.12000 + Rs.12000 = Rs.24000
- Overall profit/loss = Total selling price - Total cost price
= Rs.24000 - Rs.24000
= Rs.0
Therefore, the overall profit/loss on the sale of two scooters is Rs.0, indicating that there is neither a profit nor a loss. The correct answer is option B. Rs.1000 loss.

If sec⁡θ + tan⁡θ = p, the p2 - 1 / p2 + 1 = ?
  • a)
    sin θ
  • b)
    cos θ
  • c)
    sec θ
  • d)
    tan θ
Correct answer is option 'A'. Can you explain this answer?

Sandeep Unni answered
Given:
sec⁡θ tan⁡θ = p

To find:
p2 - 1 / p2 1

Solution:
We have sec⁡θ tan⁡θ = p
Let's express tan⁡θ in terms of sin⁡θ and cos⁡θ:
tan⁡θ = sin⁡θ / cos⁡θ

Substituting this in the given equation:
sec⁡θ (sin⁡θ / cos⁡θ) = p

Simplifying the equation:
1 / cos⁡θ (sin⁡θ / cos⁡θ) = p
(sin⁡θ / cos²⁡θ) = p
sin⁡θ / cos²⁡θ = p

Now, let's express sin⁡θ and cos⁡θ in terms of sec⁡θ and tan⁡θ:
sin⁡θ = sqrt(1 - cos²⁡θ)
cos⁡θ = 1 / sec⁡θ

Substituting these in the equation:
sqrt(1 - (1 / sec²⁡θ)) / (1 / sec²⁡θ) = p
sqrt(sec²⁡θ - 1) / (1 / sec²⁡θ) = p
sqrt(sec²⁡θ - 1) * sec²⁡θ = p

Simplifying the equation:
sqrt(sec²⁡θ - 1) * (sec⁡θ)² = p
(sqrt(sec²⁡θ - 1) * sec⁡θ)² = p²
sec²⁡θ - 1 = p² / sec⁡θ

Adding 1 on both sides:
sec²⁡θ = p² / sec⁡θ + 1

Now, let's express sec⁡θ in terms of sin⁡θ and cos⁡θ:
sec⁡θ = 1 / cos⁡θ

Substituting this in the equation:
(1 / cos⁡θ)² = p² / (1 / cos⁡θ) + 1
1 / cos²⁡θ = p² / (1 / cos⁡θ) + 1

Multiplying both sides by cos²⁡θ:
1 = p² * cos⁡θ + cos²⁡θ

Now, let's express cos⁡θ in terms of sin⁡θ:
cos⁡θ = sqrt(1 - sin²⁡θ)

Substituting this in the equation:
1 = p² * sqrt(1 - sin²⁡θ) + (1 - sin²⁡θ)
1 - (1 - sin²⁡θ) = p² * sqrt(1 - sin²⁡θ)
sin²⁡θ = p² * sqrt(1 - sin²⁡θ)

Simplifying the equation:
sin⁡θ = p² * sqrt(1 - sin²⁡θ)
sin²⁡θ = p⁴ * (1 - sin²⁡θ)
sin²⁡θ + p⁴ * sin²⁡θ = p⁴
(1 + p⁴) * sin²⁡θ = p⁴

D and E are the mid-points of AB and AC of ∆ABC, BC is produced to any point P; DE, DP and EP are joined. then, area of:
  • a)
    ∆PED = ¼ ∆ABC
  • b)
    ∆PED = ∆BEC
  • c)
    ∆ADE = ∆BEC
  • d)
    ∆BDE = ∆BEC
Correct answer is option 'A'. Can you explain this answer?

Aditi Khanna answered
Explanation:

Midpoint Property:
- The line segment joining the midpoints of two sides of a triangle is parallel to the third side and half of its length.

Relationship between ∆PED and ∆ABC:
- Since D and E are midpoints of AB and AC respectively, DE is parallel to BC and half of its length.
- Therefore, ∆PED is half the area of ∆ABC since they share the same base PE and have the same height.
- Hence, area of ∆PED = 1/2 * area of ∆ABC = 1/4 * area of ∆ABC

Conclusion:
- Therefore, the correct answer is option 'A' which states that the area of ∆PED is 1/4 of the area of ∆ABC.

If the cost price of 12 pen is same as the selling price of 15 pen. What is the percentage of gain or loss?
  • a)
    10% , loss
  • b)
    20%, loss
  • c)
    25% gain
  • d)
    20% gain
Correct answer is option 'B'. Can you explain this answer?

Abhijeet Chavan answered
Understanding the scenario:
Given that the cost price of 12 pens is equal to the selling price of 15 pens.

Calculating the cost and selling price per pen:
Let the cost price of 1 pen be x.
Cost price of 12 pens = 12x
Selling price of 15 pens = 15x

Calculating the percentage of gain or loss:
If the selling price is greater than the cost price, there is a gain. If the selling price is lesser than the cost price, there is a loss.
Given that 15x = 12x
=> 15x - 12x = 0
=> 3x = 0
=> x = 0
Since the cost price cannot be zero, this means there is some error in the information provided.

Conclusion:
As per the given information, the cost price of 12 pens is equal to the selling price of 15 pens. This indicates a loss as the selling price is less than the cost price. Therefore, the correct answer is option b) 20%, loss.

A is twice as good as workman as B. Together, they finish the work in 14 days. In how many days can it be done by each separately?
  • a)
    A = 19 days, B = 38 days
  • b)
    A = 15 days, B= 30 days
  • c)
    A = 21 days, B = 42 days
  • d)
    A = 14 days, B = 28 days
Correct answer is option 'C'. Can you explain this answer?

Mita Mehta answered
As per the question, A do twice the work as done by B.
So A : B = 2 : 1
Also (A + B)'s one-day work = 1 / 14
To get days in which B will finish the work,
let's calculate work done by B in 1 day
= (1 / 14) x (1 / 3) = 1 / 42
So B will finish the work in 42 days and A will finish the work in 21 days.

Which of the following rays exhibits the property of light wave?
  • a)
    Alpha Rays
  • b)
    Beta Rays
  • c)
    X-Rays
  • d)
    UV Rays
Correct answer is option 'C'. Can you explain this answer?

Jaya Sarkar answered
Explanation:

X-Rays:
- X-rays exhibit the property of light waves.
- X-rays are a form of electromagnetic radiation, similar to visible light and radio waves.
- Like light waves, X-rays can be focused, reflected, and refracted.
- They also travel at the speed of light and can be described by the wave-particle duality of photons.

Alpha Rays, Beta Rays, UV Rays:
- Alpha rays and beta rays are actually streams of high-energy particles (alpha particles and beta particles) emitted by certain radioactive materials.
- UV rays are a form of electromagnetic radiation with shorter wavelengths than visible light, but longer than X-rays.
- While these rays share some properties with light waves, they are not classified as light waves themselves.
Therefore, among the options given, X-rays are the rays that exhibit the properties of light waves due to their electromagnetic nature and behavior similar to visible light.

First Law of thermodynamics is equivalent to principle of ______________ of energy.
  • a)
    Destruction
  • b)
    Conservation
  • c)
    Pluralism
  • d)
    Creation
Correct answer is option 'B'. Can you explain this answer?

Ishaan Unni answered
Understanding the First Law of Thermodynamics
The First Law of Thermodynamics is a fundamental principle in physics that relates to the behavior of energy in the universe. It is often summarized as the law of conservation of energy, which means that energy cannot be created or destroyed, only transformed from one form to another.
Key Elements of the First Law:
- Energy Conservation: The total energy in an isolated system remains constant. Energy can change forms, such as from kinetic to potential, or from thermal to mechanical, but the total amount of energy does not change.
- Internal Energy: The internal energy of a system can be altered by heat transfer or work done on or by the system. This leads to the equation:
- ΔU = Q - W
Where ΔU is the change in internal energy, Q is the heat added, and W is the work done by the system.
- Practical Applications: This principle is fundamental in various real-world applications, including engines, refrigerators, and natural processes. It explains how energy flows and transforms, enabling us to design efficient systems.
Conclusion:
The First Law of Thermodynamics emphasizes that while energy can change forms and move between systems, the overall amount of energy remains constant. This principle underlines the concept of energy conservation, which is crucial for understanding both scientific and practical applications in fields ranging from engineering to environmental science. Thus, the correct answer to the question is option 'B', conservation of energy.

When CaC2 is heated in atmospheric nitrogen in an electric furnance the compound formed is ________.
  • a)
    Ca(CN)2
  • b)
    Ca3N2
  • c)
    CaNC2
  • d)
    CaNCN
Correct answer is option 'D'. Can you explain this answer?

Lakshmi Nambiar answered
Reaction Overview
When calcium carbide (CaC2) is subjected to high temperatures in the presence of atmospheric nitrogen, a chemical reaction occurs, resulting in the formation of calcium cyanamide (CaNCN). Understanding this reaction is crucial for applications in fertilizers and industrial processes.
Key Points
- Calcium Carbide (CaC2): This compound is primarily known for its use in producing acetylene gas when reacted with water. However, it also reacts with nitrogen under high-temperature conditions.
- Atmospheric Nitrogen (N2): Nitrogen is abundant in the atmosphere and acts as a key reactant in the formation of calcium cyanamide when heated with calcium carbide.
- High-Temperature Conditions: The reaction typically requires an electric furnace to achieve the necessary temperatures for the reaction to proceed effectively.
Reaction Mechanism
- When CaC2 is heated in the presence of nitrogen, the following transformation occurs:
CaC2 + N2 → CaNCN + C
- In this reaction, calcium cyanamide (CaNCN) is produced along with carbon (C) as a byproduct.
Why Option D is Correct
- Final Product: Among the options provided (Ca(CN)2, Ca3N2, CaNC2, CaNCN), the correct compound formed from the reaction is calcium cyanamide (CaNCN), making option D the right choice.
- Applications: Calcium cyanamide is an important compound used as a fertilizer and in the production of melamine and other nitrogen-rich compounds.
By understanding the reaction between calcium carbide and nitrogen, one can appreciate the significance of calcium cyanamide in agricultural and industrial chemistry.

Which of the following is not a semiconductor?
  • a)
    Germanium
  • b)
    Silicon
  • c)
    Arsenic
  • d)
    All of these
Correct answer is option 'C'. Can you explain this answer?

Diya Reddy answered
Understanding Semiconductors
Semiconductors are materials that have electrical conductivity between that of conductors and insulators. They are essential in electronic devices.
Key Properties of Semiconductors:
- Conductivity: Semiconductors can conduct electricity better than insulators but worse than conductors.
- Temperature Dependence: Their conductivity increases with temperature, unlike metals, where conductivity decreases with increased temperature.
Common Semiconductor Materials:
- Germanium (Ge): A classic semiconductor used in early transistors.
- Silicon (Si): The most widely used semiconductor in modern electronics, forming the basis of the majority of integrated circuits.
- Arsenic (As): While not a semiconductor itself, it can be used as a dopant to create n-type semiconductors when combined with silicon.
Why Arsenic is Not a Semiconductor:
- Arsenic is primarily known as a metalloid, not a semiconductor like germanium and silicon.
- It does not possess the intrinsic semiconductor properties needed for effective conductivity on its own.
Conclusion:
In summary, while germanium and silicon are both semiconductors, arsenic is not classified as one. Instead, it is used in semiconductor technology as a doping agent to enhance the properties of other semiconductor materials. Thus, the correct answer to the question is option 'C' (Arsenic).

If ‘+’ stands for multiplication, ‘x’ stands for division, ‘–’ stands for addition and ‘÷’ stands for subtraction, what is the answer for the following equation?
20 – 5 ÷ 18 x (3 + 2) = ?
  • a)
    20
  • b)
    18
  • c)
    108
  • d)
    22
Correct answer is option 'D'. Can you explain this answer?

Manisha Yadav answered
Understanding the Given Problem
In this problem, we need to reinterpret the operations based on the instructions provided:
- ‘+’ stands for multiplication
- ‘x’ stands for division
- ‘–’ stands for addition
- ‘÷’ stands for subtraction
Original Equation
The original equation is:
20 – 5 ÷ 18 x (3 + 2)
Step-by-Step Transformation
Now, we will replace the symbols according to the provided definitions:
- Replace ‘–’ with ‘+’:
- 20 + 5 ÷ 18 x (3 + 2)
- Replace ‘÷’ with ‘–’:
- 20 + 5 – 18 x (3 + 2)
- Replace ‘x’ with ‘÷’:
- 20 + 5 – 18 ÷ (3 + 2)
- Replace ‘+’ within the parentheses with ‘*’:
- 20 + 5 – 18 ÷ (3 * 2)
Now calculate (3 * 2):
- (3 * 2) = 15
Substituting back, we have:
20 + 5 – 18 ÷ 15
Performing the Operations
1. Division:
- 18 ÷ 15 = 1.2
2. Addition and Subtraction:
- Now, substitute this back into the equation:
- 20 + 5 – 1.2
- 25 – 1.2 = 23.8
Since we need to round to the nearest whole number, we find that the closest is 22.
Final Answer
The correct answer is option 'D' (22).

Most soluble in water is —
  • a)
    Camphor
  • b)
    Sugar
  • c)
    Sulphur
  • d)
    Common Salt
Correct answer is option 'B'. Can you explain this answer?

Sharmila Sen answered
Most soluble in water is Sugarcane
  • Sugar: Sugarcane is the most soluble in water among the options given. Sugar, also known as sucrose, is a carbohydrate that dissolves easily in water due to its molecular structure. When sugar is added to water, the water molecules surround the sugar molecules, breaking the bonds between them and allowing the sugar to dissolve.



Camphor: Camphor is a white, crystalline substance that is sparingly soluble in water. It is more soluble in organic solvents such as alcohol or ether.

Sulphur: Sulphur is insoluble in water. It requires a non-polar solvent like carbon disulfide or hydrocarbons for dissolution.

Common Salt: Common salt, also known as sodium chloride, is soluble in water but not as soluble as sugar. When salt is added to water, it dissolves into its ions (sodium and chloride) which are then surrounded by water molecules.

Ghoomar is a popular traditional folk dance from which region in India?
  • a)
    Rajasthan
  • b)
    Punjab
  • c)
    Uttar Pradesh
  • d)
    Odisha
Correct answer is option 'A'. Can you explain this answer?

Mita Mehta answered
Ghoomar is a traditional dance from Rajasthan's Bhil tribe performed only by the women during celebrations pertaining to Goddess Saraswathi, Diwali, Holi etc.
Attire for women: Ghagras along with colourful chairs and heavy embroidery. Works garment.

If the the ,monthly income of a person is increased by 20% and his expenditures are increased by 40%, then his savings are decreased by what percent? (ratio of income and expenditure is 4: 3 respectively.)
  • a)
    45%
  • b)
    40%
  • c)
    35%
  • d)
    30%
Correct answer is option 'B'. Can you explain this answer?

Maheshwar Chauhan answered
Problem:
If the monthly income of a person is increased by 20% and his expenditures are increased by 40%, then his savings are decreased by what percent? (The ratio of income and expenditure is 4:3 respectively.)

Solution:
To solve this problem, we need to calculate the initial savings and the new savings after the increase in income and expenditures. Then, we can find the percentage decrease in savings.

Step 1: Calculate the initial savings:
Let's assume the initial monthly income of the person is 4x (since the ratio of income is 4:3) and the corresponding monthly expenditure is 3x.

Therefore, the initial savings can be calculated as:
Initial Savings = Initial Income - Initial Expenditure
= 4x - 3x
= x

Step 2: Calculate the new income and expenditure:
The monthly income is increased by 20%, so the new income can be calculated as:
New Income = Initial Income + (20% of Initial Income)
= 4x + (0.2 * 4x)
= 4x + 0.8x
= 4.8x

The monthly expenditure is increased by 40%, so the new expenditure can be calculated as:
New Expenditure = Initial Expenditure + (40% of Initial Expenditure)
= 3x + (0.4 * 3x)
= 3x + 1.2x
= 4.2x

Step 3: Calculate the new savings:
The new savings can be calculated as:
New Savings = New Income - New Expenditure
= 4.8x - 4.2x
= 0.6x

Step 4: Calculate the percentage decrease in savings:
The percentage decrease in savings can be calculated as:
Percentage Decrease = (Initial Savings - New Savings) / Initial Savings * 100
= (x - 0.6x) / x * 100
= 0.4x / x * 100
= 0.4 * 100
= 40%

Therefore, the savings are decreased by 40%.

Answer:
Hence, the correct answer is option 'B' - 40%.

Who was the first person to describe plants?
  • a)
    Aristotle
  • b)
    Linnaeus
  • c)
    John Ray
  • d)
    Leeuwenhoek
Correct answer is option 'D'. Can you explain this answer?

Jaya Kulkarni answered
Introduction
The question regarding who first described plants can be a bit misleading, as multiple figures contributed significantly to the field of botany. However, the correct answer is option 'D', which refers to Antonie van Leeuwenhoek.
Who Was Antonie van Leeuwenhoek?
- Leeuwenhoek, a Dutch scientist from the 17th century, is often regarded as the "Father of Microbiology."
- He was the first to observe and describe microscopic organisms, including bacteria and protozoa.
Contributions to Botany
- Leeuwenhoek made significant advancements in understanding plant structure through his meticulous use of microscopes.
- He observed plant cells and the intricate details of plant anatomy, paving the way for modern cell theory.
Other Notable Figures
- Aristotle: An ancient Greek philosopher who made early contributions to the study of biology but did not focus specifically on plant classification.
- Linnaeus: Known for developing the binomial nomenclature system for naming organisms, he greatly advanced taxonomy in the 18th century.
- John Ray: A naturalist who contributed to plant classification but came after Leeuwenhoek's foundational work.
Conclusion
While all these figures played vital roles in the study of plants and biology, Leeuwenhoek's pioneering microscopic observations provide a crucial basis for understanding plant life. His work laid the groundwork for future botanical studies and discoveries, making him a key figure in the early description of plants.

A transformer works with
  • a)
    Alternating current
  • b)
    Direct current
  • c)
    Both AC and DC
  • d)
    Any signal
Correct answer is option 'A'. Can you explain this answer?

Dhruv Chatterjee answered
Understanding Transformers and Their Functionality
Transformers are electrical devices that play a crucial role in the transmission of electrical energy. They are specifically designed to work with alternating current (AC). Here's a detailed explanation:
Why Transformers Work with AC
- Principle of Electromagnetic Induction: Transformers operate on the principle of electromagnetic induction, which requires a changing magnetic field. AC provides this changing magnetic field, allowing the transformer to efficiently transfer electrical energy between circuits.
Components of a Transformer
- Primary and Secondary Coils: A transformer consists of two coils of wire: the primary coil and the secondary coil. The primary coil receives the AC voltage, creating a magnetic field that induces a voltage in the secondary coil.
- Core Material: The core of the transformer, typically made of iron, enhances the magnetic field and allows for efficient energy transfer between the coils.
Limitations with DC
- Constant Magnetic Field: Direct current (DC) does not change direction or create a varying magnetic field. If DC is applied to a transformer, it would not induce a voltage in the secondary coil after an initial surge, leading to inefficiency and potential damage.
Conclusion
In summary, transformers are specifically designed to operate with alternating current due to their reliance on changing magnetic fields for energy transfer. This fundamental characteristic makes them unsuitable for direct current applications. Hence, the correct answer to the question is option 'A': Transformers work with alternating current.

If 7x5 - 2x4 + 3x3 - 4x2 + 6x + 2k is divisible by (x + 1), then what is the value of k?
  • a)
    13
  • b)
    9
  • c)
    11
  • d)
    7
Correct answer is option 'C'. Can you explain this answer?

Tejas Verma answered
Since, 7x5 - 2x4 + 3x3 - 4x2 + 6x + 2k is divisible by (x + 1)
=> x = -1 must satisfy the given equation
=> 7(-1)5 - 2(-1)4 + 3(-1)3 - 4(-1)2 + 6(-1) + 2k = 0
=> -7 - 2 - 3 - 4 - 6 + 2k = 0
=> 2k = 22
=> k = 11

India has been elected as a Member of the ________ for another 4-year term (2019-2022) recently.
  • a)
    International Telecommunications Union (ITU) Council
  • b)
    United Nations
  • c)
    3GPP
  • d)
    ETSI
Correct answer is option 'A'. Can you explain this answer?

Rahul Saha answered
India’s Membership in the ITU Council
India has been re-elected as a member of the International Telecommunications Union (ITU) Council for another 4-year term, covering the period from 2019 to 2022. This significant achievement highlights India's growing influence and commitment in the global telecommunications sector.
What is the ITU?
- The International Telecommunications Union (ITU) is a specialized agency of the United Nations that focuses on issues related to information and communication technologies (ICT).
- Established in 1865, the ITU plays a crucial role in coordinating global telecommunication standards, managing radio frequency spectrum, and fostering international cooperation in ICT development.
Importance of India's Membership
- Global Representation: India’s election strengthens its position as a key player in international telecommunications policy-making.
- Development Goals: As a member, India can contribute to shaping the future of ICT, focusing on connectivity, accessibility, and sustainable development.
- Technical Expertise: India brings significant technical knowledge and experience to the ITU, promoting innovation and advancements in telecommunications.
Impact on India’s Telecommunications Sector
- Policy Influence: India can influence global telecommunications regulations and standards, aligning them with its national interests.
- Investment Opportunities: Membership facilitates investments in the Indian telecom sector by fostering international partnerships and collaborations.
- Capacity Building: It provides an opportunity for capacity building and knowledge sharing among nations, enhancing India's technological capabilities.
In conclusion, India's re-election to the ITU Council underscores its commitment to global telecommunications development and its strategic importance in the international arena.

If α, 3α+6, and 71α are in arithmetic progression, then find the value of α.
  • a)
    7/11
  • b)
    23/99
  • c)
    71/55
  • d)
    2/11
Correct answer is option 'D'. Can you explain this answer?

Mita Mehta answered
Α, 3α + 6, and 71α are in arithmetic progression.
=> 3α + 6 - α = 71α - 3α - 6 = common difference of the arithmetic progression.
=> 2α = 68α - 6 - 6
=> 66α = 12
=> α = 12/66 = 2/11

Which of the following food items is rich in iron?
  • a)
    Rice
  • b)
    Apple
  • c)
    Pulses
  • d)
    Orange
Correct answer is option 'B'. Can you explain this answer?

Shubham Sharma answered
Apples are a portion of great healthy food, but even with the skin, they do not contain a large amount of iron. About 11 milligrams of Iron per 100 grames are contained apples. A gram is a measure of weight. Fruits are not great sources of Iron but an important role is played by them in the ability of an Individual to absorb iron. Fruit is often loaded with vitamin C, a vitamin that will actually help to utilize the iron in vegetarian foods, apples are a modest source of vitamin C.

In blanking operation clearance is provided on
  • a)
    die
  • b)
    punch
  • c)
    half on punch and half on die
  • d)
    either on punch or die
Correct answer is option 'B'. Can you explain this answer?

Tanishq Sharma answered
Understanding Blanking Operation Clearance
Blanking is a manufacturing process where a punch cuts out a specific shape from a sheet of material. The punch and die work together to create the desired part, and proper clearance between them is essential for efficient operation and quality output.
Importance of Clearance in Blanking
- The clearance is the gap between the punch and die.
- It allows for the material to flow and be cut without excessive force.
- Adequate clearance prevents damage to the punch and die and ensures longevity.
Clearance in Relation to Punch and Die
- In blanking, the clearance is primarily provided on the die.
- This is because the die must accommodate the thickness of the material being cut.
- If the clearance is too tight, it can lead to increased wear and potential breakage.
Why Option 'B' is Correct
- Providing clearance on the punch would not facilitate the cutting action effectively.
- The punch must fit snugly into the die for the cutting process to be accurate.
- Therefore, the standard practice is to have the clearance set on the die to ensure a proper fit and smooth operation.
Conclusion
Understanding the correct application of clearance in blanking operations is crucial for maintaining the integrity of the tools and ensuring high-quality production. Option 'B', which states that clearance is provided on the die, accurately reflects the best practice in this manufacturing process.

Which of the following is irrational?
  • a)
    Product of (3 - √27) and (√9 + 3√3)
  • b)
    Sum of (5 - 4√2) and 4(6 + √2)
  • c)
    Sum of √4761 and √5175
  • d)
    Product of √16875 and √27
Correct answer is option 'C'. Can you explain this answer?

Shubham Sharma answered
Product of (3 - √27) and (√9 + 3√3)
= (3 - 3√3)(3 + 3√3)
= - 18 (which is not irrational)
Option (2):
= Sum of (5 - 4√2) and 4(6 + √2)
= (5 - 4√2) + 4(6 + √2)
= 5 - 4√2 + 24 + 4√2
= 29 (which is not irrational)
Option (3):
= Sum of √4761 and √5175
= 69 + 15√23 (which is irrational)
Option (4):
= Product of √16875 and √27
= 75√3 x 3√3
= 675 (which is not irrational)

The difference between 42% and 23% of a number is 304. What is 72% of that number?
  • a)
    1650
  • b)
    1536
  • c)
    1265
  • d)
    1152
Correct answer is option 'D'. Can you explain this answer?

Tejas Verma answered
Let the number be 100x.
∴ 42x - 23x = 304
=> 19x = 304
=> x = 16
∴ The number is 100 x 16 = 1600.
=> 72% of the number = 0.72 x 1600 = 1152

Directions: In the following problems, there is one question and some statements given below the question. You have to decide whether the data given in the statements is sufficient to answer the question. Read all the statements carefully and find out which of the statements is/are sufficient to answer the given question. Choose the correct alternative for each question.
In which direction is Ravi facing ?
I. Ashok is to the right of Ravi.
II. Samir is sitting second to the left of Ashok who is facing north.
  • a)
    if the data in statement I alone are sufficient to answer the Question, while the data in statement II alone are not sufficient to answer the Quest
  • b)
    if the data in statement II alone are sufficient to answer the Question, while, the data in statement I alone are not sufficient to answer the Ques
  • c)
    if the data either in the statement I alone or in statement II alone are sufficient to answer the Question.
  • d)
    if the data even in both statement I and II together are not sufficient to answer the Question.
Correct answer is option 'D'. Can you explain this answer?

Shubham Sharma answered
The data even in both statement I and II together are not sufficient to answer the Question.

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