The price (per litre) of petrol increases by 40%. By what percent should its consumption be reduced such that the expenditure on it increases by 19% only?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 15% .
Let original price = 100, new price = 140 (40% increase)
Let original consumption = 1 litre, cost = 100
New expenditure = 119 (19% increase)
New consumption = 119 / 140 = 0.85 litre
Reduction = 1 − 0.85 = 0.15 litre
% reduction = (0.15 / 1) × 100 = 15%