If the price of gasoline increases by 25% and a driver intends to spend only 5% more on gasoline, by how much percent should the driver reduce the quantity of gasoline that he buys? Choose the correct answer:
A) 20 %
B) 16 %
C) 15 %
D) 12 %
E) 10 %

Rationale: "let x be the amount of gasoline the driver buys originally . let y be the new amount of gasoline the driver should buy . let p be the original price per liter . ( 1.25 * p ) y = 1.05 ( p * x ) y = ( 1.05 / 1.25 ) x = 0.84 x which is a reduction of 16 % . the answer is b ."
Answer: B