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 26% only?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 28% .
Let original price = P and consumption = C
Original expenditure = P × C
New price = 1.75P
Let reduction in consumption = x%
New consumption = C × (1 − x/100)
New expenditure = 1.75P × C × (1 − x/100)
According to question, new expenditure = 1.26 × P × C
So, 1.75(1 − x/100) = 1.26
1 − x/100 = 1.26 ÷ 1.75
1 − x/100 = 0.72
x/100 = 1 − 0.72 = 0.28
x = 28