A certain car uses one gallon of gasoline every 32 miles when it travels on highway, and one gallon of gasoline every 20 miles when it travels in the city. When a car travels 4 miles on highway and 4 additional miles in the city, it uses what percent more gasoline than if it travels 8 miles on the highway? Choose the correct option: A) 15% B) 20% C) 22.5% D) 25% E) 30%
4 miles on the highway = 4/32 gallons;   4 miles in the city = 4/20 gallons;   Total = 4/32 + 4/20 = 13/40 gallons.   8 miles on the highway = 8/30 gallons .   The % change = (13/40 - 8/32)/(8/32) = 0.30.   Answer: 30%.
<result>E</result>
A certain car uses one gallon of gasoline every 32 miles when it travels on highway, and one gallon of gasoline every 20 miles when it travels in the city. When a car travels 4 miles on highway and 4 additional miles in the city, it uses what percent more gasoline than if it travels 8 miles on the highway?