If the price of petrol increases by 35% and Benson intends to spend only an additional 15% on petrol, by how much % will he reduce the quantity of petrol purchased?

The correct option is B

15%

Let the price of petrol be ‘x’ and Benson purchases ‘y’ litres of petrol

Therefore, he would have spent Rs.xy

New price per litre of petrol =$\frac{35x}{100}+x=\frac{135x}{100}=1.35x$

Benson williing to spend = xy + 15% of xy = 1.15xy

Let the new quantity of petrol that he can get be ‘q’

q = $\frac{1.15xy}{1.35x}=\frac{1.15y}{1.35}=0.85y$

As the new quantity that he can buy is 0.85y, he gets 0.15y lesser than what he used to get earlier.

Or a reduction of 0.15*100 = 15%