A certain car uses one gallon of gasoline every 36 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 one:
A) 15%  B) 20%  C) 22.5%  D) 25%  E) 40%
4 miles on the highway = 4/36 gallons;   4 miles in the city = 4/20 gallons;   Total = 4/36 + 4/20 = 14/45 gallons.   8 miles on the highway = 8/30 gallons .   The % change = (14/45 - 8/36)/(8/36) = 0.40.   Answer: 40%.
<result>E</result>
A certain car uses one gallon of gasoline every 36 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?