A certain car uses one gallon of gasoline every 40 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 choice
A) 15% B) 20% C) 22.5% D) 25% E) 50%
4 miles on the highway = 4/40 gallons;   4 miles in the city = 4/20 gallons;   Total = 4/40 + 4/20 = 3/10 gallons.   8 miles on the highway = 8/40 gallons .   The % change = (3/10 - 8/40)/(8/40) = 1/2 = 0.50.   Answer: 50%.
<result>E</result>
A certain car uses one gallon of gasoline every 40 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?