1 Crore+ students have signed up on EduRev. Have you? 
The price of wheat is reduced by 4%. How many more or less kg of wheat can now be bought for the money which was sufficient to buy 48 kg wheat earlier?
Given:
The price of wheat is reduced by 4%.
Assumption:
Let the price of wheat be Rs.100/kg.
Calculation:
The price of 48 kg wheat = 4800
As price is reduce by 4% it means that it became 96% of initial 100% hence,
After price decrease = 4800/96 = 50 kg
Hence, the required quantity of wheat = (50 – 48) = 2 kg more.
The difference between the 30% of a number and 22% of that number is 4800. What is the 18% of that number?
Given:
Difference between the 30% of a number and 22% of the same number = 4800
Calculation:
Let the number be P
According to the question,
30% of P – 22% of P = 4800
⇒ 8% of P = 4800
⇒ P = 60,000
And, 18% of P = (18/100) × 60,000 = 10,800
∴ 18% of P is 10,800
Kamal saves x% of her monthly income. When her monthly expenditure is increased by 20% and the monthly income is increased by 26%, then her monthly savings increased by 60%. What is the value of x?
Given:
Kamal saves x% of her income
Increase in his income = 26%
Increase in his expenditure = 20%
Increase in saving = 60%
Concept used:
Income = Saving + Expenditure
Calculations:
Let income of Kamal be 100
Saving of Kamal = 100 × (x/100) = x
Expenditure of Kamal = 100 – x
Kamal's salary after increment = 100 × (126/100) = 126
Kamal's expenditure after increment = (100 – x) × 120/100 = (100 – x) × 6/5
New Saving = 126 – (100 – x) × 6/5 (1)
New saving after increment = x × 160/100
New saving after increment = 8x/5 (2)
From eq. (1) and eq. (2)
⇒ 126 – (100 – x) × 6/5 = 8x/5
⇒ 126 – 120 + 6x/5 = 8x/5
⇒ 6 = (8x/5) – (6x/5)
⇒ 6 = (8x – 6x)/5
⇒ 30 = 2x
⇒ x = 15
∴ The value of x is 15
Shortcut Trick:
A and B are two fixed points 5 cm apart and C is a point on AB such that AC is 3 cm. If the Length of AC is increased by 6%, the length of CB is decreased by how many %?
Increase in AC = 6%
Increase in AC =
Decrease in CB = 5  3.18 = 1.82 cm
Decrease = 2  1.82 = 0.18 cm
So Percentage decrease
In an election, there is neck to neck competition between two candidates A and B. Candidate A got 54% of valid votes and won by 3200 votes. If 20% of the votes cast in the election are invalid. Then find the total votes cast in the election.
Given:
Invalid votes = 20% of total votes
Percentage of votes candidate A gets = 54% of valid votes
The difference of votes in Candidates A and B = 3200
Concept used:
By using the concept of percentage
Calculation:
Let the total number of valid votes cast in the election be x.
Invalid votes = 20% of Total votes
Votes got by A = 54% of valid votes
⇒ Votes got by A = 54/100 × x
Votes got by B = (100%  54%) of valid votes
⇒ Votes got by B = 46% of valid votes
⇒ Votes got by B = 46/100 × x
Required difference = Votes got by A – Votes got by B
⇒ 3200 = (54/100 × x) – (46/100 × x)
⇒ 3200 = 8/100 × x
⇒ x = 40000
Total valid votes = 40000
Total valid votes = 80% of total votes cast
⇒ 40000 = 80/100 × Total votes cast
⇒ Total votes = 50000
∴ The total votes cast in the election is 50000.
800 g of sugar solution has 40% sugar in it. How much sugar should be added to make its proportion at 60% in the solution?
Calculation:
Quantity of sugar in solution = 800 × (40/100) = 320 gm
Let the quantity of sugar added be x gm.
According to the question
⇒ (320 + x)/(800 + x) = 60/100
⇒ (320 + x)/(800 + x) = 3/5
⇒ (320 + x) × 5 = 3 × (800 + x)
⇒ 1600 + 5x = 2400 + 3x
⇒ 5x – 3x = 2400 – 1600
⇒ x = 400 gm
Shortcut Trick:
40% 100%
60%
40 : 20
2 : 1
2 unit = 800 g
1 unit = 400 g
The difference between the 41% of a number and 33% of that number is 960. Then, what is the value of 33.33% of that number?
Given:
The difference between the 41% of a number and 33% of that number is 960.
33.33% = 1 / 3
Calculation:
Suppose the number is N.
∴ 41% of N – 33% of N = 960
⇒ 8% of N = 960
⇒ N = (960 × 100) / 8
⇒ N = 12,000
According to question:
⇒ 33.33% of N = 1 / 3 of 12,000 = 4,000
The price of sugar is increased by 25%. If a family wants to keep its expenses on sugar unaltered, then the familiy will have to reduce the consumption of sugar by:
Given:
Increase % in the price of sugar = 25%
Formula used:
Expense = Price × Quantity
Calculation:
Let the initial expenses on sugar was Rs.100
Now, the price rises by 25%
⇒ New price = (100 + 100 × 25%) = 125
In order to keep the expense unaltered, Rs.25 has to be cut from Rs.125.
⇒ 125  25 = 100
∴ The decrease in the consumption = 25/125 × 100 = 20%
Alternate Method:
Reduction % = (Old quantity  New quantity)/Old quantity ×100
Let the price of 1 kg sugar = Rs.20
Let the the quantity of sugar bought = 5 kg
⇒ Expense = Price × Consumption = 20 × 5 = Rs.100
After increase of 25% in the price = Rs.20 × 125/100 = Rs.25
To keep the expense unchanged, that is Rs.100
⇒ New consumption = Rs.100/25 = 4 kg
Reduce in the consumption = 5 kg  4 kg = 1 kg
∴ Percentage reduction in consumption = 1/5 × 100 = 20%
Shortcut Trick:
100 → + 25% → 125 _____  Y% → 100
Now, Y = 25/125 × 100 = 20%
A student got 20% marks and failed by 72 marks. If he scores 40% marks then he gets 8 marks more than the passing marks. Find the passing marks.
Given:
A student got 20% marks and failed by 72 marks. If he scores 40% marks then he gets 8 marks more than the passing marks.
Concept:
Percentage.
Solution:
Let total marks be x
20% of total marks + 72 = 40% of total marks  8
⇒ (20/100)x + 72 = (40/100)x  8
⇒ (x/5) + 72 = (2x/5)  8
⇒ x/5 = 80
⇒ x = 400 = total marks
Hence, passing marks
⇒ (x/5) + 72 = (400/5) +72
⇒ 152
∴ The passing marks is 152.
Two numbers are 50% and 75% lesser than a third number. By how much percent is the second number to be enhanced to make it equal to the first number?
Let the third number = x
⇒ The first number = x  50% of x = x/2
⇒ The second number = x  75% of x = x/4
⇒ The percent by which second number has to be enhanced to make it equal to the first number = [(x/2  x/4) / (x/4)] × 100 = 100%
(It can also be seen that x/4 is just half of x/2 so it has to be multiplied twice to become the second number which is 100%)
Alternate method
Let, 3rd number be 100
Hence, 2nd number will be 25 and 1st number will be 50
Now, 2nd number should be increased by 25 to make it equal to 1st number
∴ required percentage = 25/25 × 100 = 100%
172 videos94 docs66 tests

Use Code STAYHOME200 and get INR 200 additional OFF

Use Coupon Code 
172 videos94 docs66 tests








