The price (per litre) of petrol increases by 50%. By what percent should its consumption be reduced such that the expenditure on it increases by 23% only?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 18%.
Let original price = Rs. 100 per litre
New price = 100 + 50% of 100 = Rs. 150 per litre
Let original consumption = 1 litre
Original expenditure = 100 × 1 = Rs. 100
New expenditure = 100 + 23% of 100 = Rs. 123
Let new consumption = x litres
Then, 150 × x = 123
⇒ x = 123 / 150 = 0.82 litres
Reduction in consumption = (1 - 0.82) × 100 = 18%