The price of petrol is increased by 25 %. By how much percent a car owner should reduce his consumption of petrol. So that expenditure on petrol would not be increased?

A. 25 %
B. 30 %
C. 50 %
D. 20 %

Explanation:

Reduction % in consumption = {r/(100+ r) × 100}% = (25/125 × 100)% = 20%