The price (per litre) of petrol increases by 75%. By what percent should its consumption be reduced such that the expenditure on it increases by 47% only?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 16%.
Let original price = 100, original consumption = 100
Original expenditure = 100 × 100 = 10,000
New price = 100 + 75% of 100 = 175
Let new consumption = x
New expenditure = 175 × x = 10,000 + 47% of 10,000 = 14,700
So,175 × x = 14,700
x = 14,700 / 175 = 84
Reduction in consumption = (100 - 84) = 16%