Question

The price of petrol increases by 25%. By what percentage must a customer reduce the consumption so that the earlier bill on the petrol does not alter?
1. 20%
2. 25%
3. 30%
4. 33.33%

Answer 1

Correct Answer - Option 1 : 20%

Given:

The price of petrol increased = 25%

Calculations:

Let the price of petrol initially be 100

Let the consumption be 10 litres

The total cost of consumption initially = 100 × 10

⇒ 1000

After increasing the price 25% price of petrol = 100 + 25% × 100

⇒ 100 + (25/100) × 100 = 100 + 25

⇒ 125

Now, for 1000 rupees customer can by = 1000/125

⇒ 8 liters

Consumption decreses = 10 - 8

⇒ 2

Percentage change in consumption = (2/10) × 100

⇒ 20%

∴ The required percentage is 20%
=20%