The price (per litre) of petrol increases by 85%. By what percent should its consumption be reduced such that the expenditure on it increases by 11% only?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 40%.
Let original price = 100, so new price = 100 + 85% of 100 = 185
Let original consumption = 100 units
Original expenditure = 100 × 100 = 10,000
New expenditure = 10,000 + 11% of 10,000 = 11,100
New consumption = 11,100 ÷ 185 = 60
Consumption reduced = 100 – 60 = 40%