If the price of gasoline increases by 20% and a driver intends to spend only 8% more on gasoline, by how much percent should the driver reduce the quantity of gasoline that he buys?  Choose the most appropriate option
A) 4 %
B) 5 %
C) 6 %
D) 8 %
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 . ( 1.2 * p ) y = 1.08 ( p * x ) y = ( 1.08 / 1.2 ) x = 0.9 x which is a reduction of 10 % . the answer is e ."
Answer: E