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All questions of Numerical relations and reasoning for Mechanical Engineering Exam

An institute organised a fete and 1/5 of the girls and 1/8 of the boys participated in the same. What fraction of the total number of students took part in the fete ?
  • a)
    2/13
  • b)
    13/40
  • c)
    Data inadequate
  • d)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Suppose ther are 18 students (10 girls, 8 boys).1/5 of 10=2 (girls).1/8 of 8=1 (boy).Total participation=2+1=3.Total students=10+8=18.
Answer = 3/18 = 1/6.
Answer cannot be determined until we have the Ratio of girls to boys.

If you write down all the numbers from 1 to 100, then how many times do you write 3 ?
  • a)
    11
  • b)
    18
  • c)
    20
  • d)
    21
Correct answer is option 'C'. Can you explain this answer?

Ishani Rane answered
Clearly, from 1 to 100, there are ten numbers with 3 as the unit's digit- 3, 13, 23, 33, 43, 53, 63, 73, 83, 93; and ten numbers with 3 as the ten's digit - 30, 31, 32, 33, 34, 35, 36, 37, 38, 39.
So, required number = 10 + 10 = 20.

12 year old Manick is three times as old as his brother Rahul. How old will Manick be when he is twice as old as Rahul ?
  • a)
    14 years
  • b)
    16 years
  • c)
    18 years
  • d)
    20 years
Correct answer is option 'B'. Can you explain this answer?

Harshad Malik answered
Manick's present age = 12 years, Rahul's present age = 4 years.
Let Manick be twice as old as Rahul after x years from now.
Then, 12 + x = 2 (4 + x) 12 + x = 8 + 2x x = 4.
Hence, Manick's required age = 12 + x = 16 years.

A is 3 years older to B and 3 years younger to C, while B and D are twins. How many years older is C to D?
  • a)
    2
  • b)
    3
  • c)
    6
  • d)
    12
Correct answer is option 'C'. Can you explain this answer?

Shreya Rane answered
Let's break down the information given in the question step by step to find the answer.

1. A is 3 years older than B:
We can represent this as A = B + 3.

2. A is 3 years younger than C:
We can represent this as A = C - 3.

3. B and D are twins:
This means that B and D have the same age. Let's represent their age as X. So, B = X and D = X.

Now, let's use these equations to find the values of A, B, C, and D.

From equation 1, we have A = B + 3.
Substituting B with X, we get A = X + 3.

From equation 2, we have A = C - 3.
Substituting A with X + 3, we get X + 3 = C - 3.

Now, let's solve the equation to find the value of C.

X + 3 = C - 3
X + 3 + 3 = C
X + 6 = C

So, we have found that C is 6 years older than X.

Now, let's compare the ages of C and D to find the answer to the question.

C = X + 6
D = X

To find the age difference between C and D, we subtract the age of D from the age of C.

C - D = (X + 6) - X
C - D = 6

Therefore, C is 6 years older than D. So, the correct answer is option C) 6.

If 100 cats kill 100 mice in 100 days, then 4 cats would kill 4 mice in how many days ?
  • a)
    1 day
  • b)
    4 days
  • c)
    40 days
  • d)
    100 days
Correct answer is option 'D'. Can you explain this answer?

Less cats, more days   
(Indirect Proportion)
Less mice, less days   (Direct Proportion)
Let the required number of days be x.
Cat 4: 100}  :: x : 100
Mice 100 :   4 
100 * 4 * x = 4 * 100 * 100 or x = (4 * 100 * 100) / (100*4) =100.

In three coloured boxes - Red, Green and Blue, 108 balls are placed. There are twice as many balls in the green and red boxes combined as there are in the blue box and twice as many in the blue box as there are in the red box. How many balls are there in the green box ?
  • a)
    18
  • b)
    36
  • c)
    45
  • d)
    None of these
Correct answer is option 'D'. Can you explain this answer?

Aditi Menon answered
Let R, G and B represent the number of balls in red, green and blue boxes respectively.
Then, .
R + G + B = 108 ...(i),
G + R = 2B ...(ii)
B = 2R ...(iii)
From (ii) and (iii), we have G + R = 2x 2R = 4R or G = 3R.
Putting G = 3R and B = 2R in (i), we get:
R + 3R + 2R = 108 6R = 108 R = 18.
Therefore Number of balls in green box = G = 3R = (3 x 18) = 54.

There are deer and peacocks in a zoo. By counting heads they are 80. The number of their legs is 200. How many peacocks are there ?
  • a)
    20
  • b)
    30
  • c)
    50
  • d)
    60
Correct answer is option 'D'. Can you explain this answer?

Ishaan Iyer answered
Let x and y be the number of deer and peacocks in the zoo respectively. Then,
x + y = 80 ...(i) and
4x + 2y = 200 or 2x + y = 100 ...(ii)
Solving (i) and (ii), we get) x = 20, y = 60.

In a cricket match, five batsmen A, B, C, D and E scored an average of 36 runs. D Scored 5 more than E; E scored 8 fewer than A; B scored as many as D and E combined; and B and C scored 107 between them. How many runs did E score ?
  • a)
    62
  • b)
    45
  • c)
    28
  • d)
    20
Correct answer is option 'D'. Can you explain this answer?

Aniket Menon answered
Total runs scored = (36 x 5) = 180.
Let the runs scored by E be x.
Then, runs scored by D = x + 5; runs scored by A = x + 8;
runs scored by B = x + x + 5 = 2x + 5;
runs scored by C = (107 - B) = 107 - (2x + 5) = 102 - 2x.
So, total runs = (x + 8) + (2x + 5) + (102 - 2x) + (x + 5) + x = 3x + 120.
Therefore 3x + 120 =180 3X = 60 x = 20.

Two bus tickets from city A to B and three tickets from city A to C cost Rs. 77 but three tickets from city A to B and two tickets from city A to C cost Rs. 73. What are the fares for cities B and C from A ?
  • a)
    Rs. 4, Rs. 23
  • b)
    Rs. 13, Rs. 17
  • c)
    Rs. 15, Rs. 14
  • d)
    Rs. 17, Rs. 13
Correct answer is option 'B'. Can you explain this answer?

Avik Choudhury answered
Let Rs. x be the fare of city B from city A and Rs. y be the fare of city C from city A.
Then, 2x + 3y = 77 ...(i) and
3x + 2y = 73 ...(ii)
Multiplying (i) by 3 and (ii) by 2 and subtracting, we get: 5y = 85 or y = 17.
Putting y = 17 in (i), we get: x = 13.

A bus starts from city X. The number of women in the bus is half of the number of men. In city Y, 10 men leave the bus and five women enter. Now, number of men and women is equal. In the beginning, how many passengers entered the bus ?
  • a)
    15
  • b)
    30
  • c)
    36
  • d)
    45
Correct answer is option 'D'. Can you explain this answer?

To solve this problem, let's break it down step by step:

Step 1: Assign variables
Let's assign variables to the number of men and women in the bus. Let M represent the number of men and W represent the number of women.

Step 2: Initial conditions
According to the problem, the number of women in the bus is half the number of men. So we can write the equation W = (1/2)M.

Step 3: Changes in city Y
In city Y, 10 men leave the bus and five women enter. So after these changes, the number of men will be M - 10 and the number of women will be W + 5.

Step 4: New conditions
The problem states that after these changes, the number of men and women is equal. So we can write the equation M - 10 = W + 5.

Step 5: Solve the equations
We have two equations:
W = (1/2)M and M - 10 = W + 5.

Substituting the value of W from the first equation into the second equation, we get:
M - 10 = (1/2)M + 5.

Multiply both sides of the equation by 2 to eliminate the fraction:
2(M - 10) = M + 10.

Expanding the equation, we get:
2M - 20 = M + 10.

Subtracting M from both sides of the equation, we get:
M - 20 = 10.

Adding 20 to both sides of the equation, we get:
M = 30.

Step 6: Calculate the number of passengers
Since M represents the number of men, and the problem states that initially the number of men and women is equal, the total number of passengers in the beginning is 2M.

Substituting the value of M, we get:
Total number of passengers = 2(30) = 60.

Therefore, the correct answer is option D) 45 passengers entered the bus in the beginning.

A, B, C, D and E play a game of cards. A says to B, "If you give me 3 cards, you will have as many as I have at this moment while if D takes 5 cards from you, he will have as many as E has." A and C together have twice as many cards as E has. B and D together also have the same number of cards as A and C taken together. If together they have 150 cards, how many cards has C got ?
  • a)
    28
  • b)
    29
  • c)
    31
  • d)
    35
Correct answer is option 'A'. Can you explain this answer?

Clearly, we have :
A = B - 3 ...(i)
D + 5 = E ...(ii)
A+C = 2E ...(iii)
B + D = A+C = 2E ...(iv)
A+B + C + D + E=150 ...(v)
From (iii), (iv) and (v), we get: 5E = 150 or E = 30.
Putting E = 30 in (ii), we get: D = 25.
Putting E = 30 and D = 25 in (iv), we get: B = 35.
Putting B = 35 in (i), we get: A = 32.
Putting A = 32 and E = 30 in (iii), we get: C = 28.

A bird shooter was askgd how many birds he had in the bag. He replied that there were all sparrows but six, all pigeons but six, and all ducks but six. How many birds he had in the bag in all?
  • a)
    9
  • b)
    18
  • c)
    27
  • d)
    36
Correct answer is option 'A'. Can you explain this answer?

Alok Sen answered
There were all sparrows but six' means that six birds were not sparrows but only pigeons and ducks.
Similarly, number of sparrows + number of ducks = 6 and number of sparrows + number of pigeons = 6.
This is possible when there are 3 sparrows, 3 pigeons and 3 ducks i.e. 9 birds in all.

A, B, C, D and E play a game of cards. A says to B, "If you give me three cards, you will have as many as E has and if I give you three cards, you will have as many as D has." A and B together have 10 cards more than what D and E together have. If B has two cards more than what C has and the total number of cards be 133, how many cards does B have ?
  • a)
    22
  • b)
    23
  • c)
    25
  • d)
    35
Correct answer is option 'C'. Can you explain this answer?

Uday Goyal answered
Problem Analysis:
Let's break down the given information:
- A says to B, "If you give me three cards, you will have as many as E has and if I give you three cards, you will have as many as D has."
- A and B together have 10 cards more than what D and E together have.
- B has two cards more than what C has.
- The total number of cards is 133.

Solution:
Let's assume the number of cards with A, B, C, D, and E as a, b, c, d, and e respectively.

From the given information, we can form the following equations:

1) A + 3 = e and B + 3 = d
(If B gives A three cards, then B will have as many cards as E has, and if A gives B three cards, then B will have as many cards as D has.)

2) A + B = D + E + 10
(A and B together have 10 cards more than what D and E together have.)

3) B = C + 2
(B has two cards more than what C has.)

4) A + B + C + D + E = 133
(The total number of cards is 133.)

From equation 1, we can write the following:
A = e - 3 and B = d - 3

Substituting these values in equation 2, we get:
(e - 3) + (d - 3) = D + E + 10
e + d - 6 = D + E + 10
e + d - D - E = 16 ...(equation 5)

Substituting the value of B from equation 3 in equation 1, we get:
C + 2 = d - 3
d = C + 5

Substituting the values of A, B, and d in equation 4, we get:
(e - 3) + (d - 3) + C + (C + 5) + E = 133
2C + E + e + d - 6 = 133
2C + E + e + C + 5 - 6 = 133 ...(substituting the value of d)
3C + E + e - 1 = 133
3C + E + e = 134 ...(equation 6)

Adding equation 5 and equation 6, we get:
e + d - D - E + 3C + E + e = 16 + 134
2e + d - D + 3C = 150

But we know that e + d - D - E = 16 from equation 5, so substituting this value, we get:
2e + 16 + 3C = 150
2e + 3C = 134 ...(equation 7)

Now, let's find the possible values of e and C.

From equation 7, we can see that e and C must be even numbers since 3C is divisible by 3 and 134 is even.

The possible values of e and C are:
e = 2, C = 44
e = 4, C = 42
e =

A shepherd had 17 sheep. All but nine died. How many was he left with ?
  • a)
    Nil
  • b)
    8
  • c)
    9
  • d)
    17
Correct answer is option 'C'. Can you explain this answer?

The question states that a shepherd had 17 sheep and all but nine died. We need to determine how many sheep the shepherd is left with.

Given:
- Initial number of sheep owned by the shepherd: 17
- All but nine sheep died

To Find:
- Number of sheep the shepherd is left with

Explanation:
To solve this problem, we need to subtract the number of sheep that died from the initial number of sheep owned by the shepherd.

Let's break down the steps to find the solution:

Step 1: Determine the number of sheep that died.
- The initial number of sheep owned by the shepherd is 17.
- All but nine sheep died, which means the number of sheep that died is 17 - 9 = 8.

Step 2: Calculate the number of sheep the shepherd is left with.
- Subtract the number of sheep that died from the initial number of sheep owned by the shepherd.
- 17 - 8 = 9

Therefore, the shepherd is left with 9 sheep after all but nine died.

Answer:
The correct answer is option c) 9.

A motorist knows four different routes from Bristol to Birmingham. From Birmingham to Sheffield he knows three different routes and from Sheffield to Carlisle he knows two different routes. How many routes does he know from Bristol to Carlisle ?
  • a)
    4
  • b)
    8
  • c)
    12
  • d)
    24
Correct answer is option 'D'. Can you explain this answer?

Prashanth Jain answered
To find the number of routes from Bristol to Carlisle, we need to multiply the number of routes from Bristol to Birmingham, Birmingham to Sheffield, and Sheffield to Carlisle.

Number of routes from Bristol to Birmingham = 4
Number of routes from Birmingham to Sheffield = 3
Number of routes from Sheffield to Carlisle = 2

Let's calculate the total number of routes from Bristol to Carlisle.

1. Number of routes from Bristol to Birmingham:
- The motorist knows four different routes from Bristol to Birmingham.

2. Number of routes from Birmingham to Sheffield:
- The motorist knows three different routes from Birmingham to Sheffield.

3. Number of routes from Sheffield to Carlisle:
- The motorist knows two different routes from Sheffield to Carlisle.

Now, let's multiply these numbers together to find the total number of routes from Bristol to Carlisle:

Total number of routes = Number of routes from Bristol to Birmingham * Number of routes from Birmingham to Sheffield * Number of routes from Sheffield to Carlisle
= 4 * 3 * 2
= 24

Therefore, the motorist knows 24 different routes from Bristol to Carlisle.

Hence, the correct answer is option D) 24.

A father is now three times as old as his son. Five years back, he was four times as old as his son. The age of the son (in years) is
  • a)
    12
  • b)
    15
  • c)
    18
  • d)
    20
Correct answer is option 'B'. Can you explain this answer?

Abhiram Patel answered
Given information:
- The father is now three times as old as his son.
- Five years back, the father was four times as old as his son.

Let's assume the current age of the son as "x" years.
According to the first statement, the current age of the father is three times that of the son, so the current age of the father is 3x years.

Five years back, the age of the son was x - 5 years, and the age of the father was 3x - 5 years.
According to the second statement, the father was four times as old as his son at that time, so we can write the equation:
3x - 5 = 4(x - 5)

Solving the equation:
3x - 5 = 4x - 20
3x - 4x = -20 + 5
-x = -15
x = 15

Therefore, the current age of the son is 15 years, which matches option B.

Explanation:
To find the age of the son, we need to solve the equation based on the given information. By assuming the current age of the son as "x" years, we can establish a relation between the ages of the father and son. Using this relation, we can derive an equation to solve for the value of "x". Solving the equation gives us the age of the son, which is 15 years.

A woman says, "If you reverse my own age, the figures represent my husband's age. He is, of course, senior to me and the difference between our ages is one-eleventh of their sum." The woman's age is
  • a)
    23 years
  • b)
    34 years
  • c)
    45 years
  • d)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Ayush Rane answered
Let x and y be the ten's and unit's digits respectively of the numeral denoting the woman's age.
Then, woman's age = (10X + y) years; husband's age = (10y + x) years.
Therefore (10y + x)- (10X + y) = (1/11) (10y + x + 10x + y)
(9y-9x) = (1/11)(11y + 11x) = (x + y) 10x = 8y x = (4/5)y
Clearly, y should be a single-digit multiple of 5, which is 5.
So, x = 4, y = 5.
Hence, woman's age = 10x + y = 45 years.

In a class of 60 students, the number of boys and girls participating in the annual sports is in the ratio 3 : 2 respectively. The number of girls not participating in the sports is 5 more than the number of boys not participating in the sports. If the number of boys participating in the sports is 15, then how many girls are there in the class ?
  • a)
    20
  • b)
    25
  • c)
    30
  • d)
    Data inadequate
  • e)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Ayush Rane answered
Let the number of boys and girls participating in sports be 3x and 2x respectively.
Then, 3x = 15 or x = 5.
So, number of girls participating in sports = 2x = 10.
Number of students not participating in sports = 60 - (15 + 10) = 35.
Let number of boys not participating in sports be y.
Then, number of girls not participating in sports = (35 -y).
Therefore (35 - y) = y + 5 2y 30 y = 15.
So, number of girls not participating in sports = (35 - 15) = 20.
Hence, total number of girls in the class = (10 + 20) = 30.

Five bells begin to toll together and toll respectively at intervals of 6, 5, 7, 10 and 12 seconds. How many times will they toll together in one hour excluding the one at the start ?
  • a)
    7 times
  • b)
    8 times
  • c)
    9 times
  • d)
    11 times
Correct answer is option 'B'. Can you explain this answer?

Prisha Shah answered
L.C.M. of 6, 5, 7, 10 and 12 is 420.
So, the bells will toll together after every 420 seconds i.e. 7 minutes.
Now, 7 x 8 = 56 and 7 x 9 = 63.
Thus, in 1-hour (or 60 minutes), the bells will toll together 8 times, excluding the one at the start.

The number of boys in a class is three times the number of girls. Which one of the following numbers cannot represent the total number of children in the class ?
  • a)
    48
  • b)
    44
  • c)
    42
  • d)
    40
Correct answer is option 'C'. Can you explain this answer?

Prisha Shah answered
Let number of girls = x and number of boys = 3x.
Then, 3x + x = 4x = total number of students.
Thus, to find exact value of x, the total number of students must be divisible by 4.

Ravi's brother is 3 years senior to him. His father was 28 years of age when his sister was born while his mother was 26 years of age when he was born. If his sister was 4 years of age when his brother was born, what were the ages of Ravi's father and mother respectively when his brother was born ?
  • a)
    32 years, 23 years
  • b)
    32 years, 29 years
  • c)
    35 years, 29 years
  • d)
    35 years, 33 years
Correct answer is option 'A'. Can you explain this answer?

Madhurima Dey answered
When Ravi's brother was born, let Ravi's father's age = x years and mother's age = y years.
Then, sister's age = (x - 28) years. So, x - 28 = 4 or x = 32.
Ravi's age = (y - 26) years. Age of Ravi's brother = (y - 26 + 3) years = (y - 23) years.
Now, when Ravi's brother was born, his age = 0 i.e. y - 23 = 0 or y = 23.

Chapter doubts & questions for Numerical relations and reasoning - General Aptitude for GATE 2025 is part of Mechanical Engineering exam preparation. The chapters have been prepared according to the Mechanical Engineering exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for Mechanical Engineering 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

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