A car traveled 462 miles per tankful of gasoline on the highway and 336 miles per tankful of gasoline in the city. If the car traveled 15 fewer miles per gallon in the city than on the highway, how many miles per gallon did the car travel in the city? Choose the correct choice from the following answers:
A) 14  B) 16  C) 21  D) 22  E) 40

Rationale: "i treat such problems as work ones . work = rate * time mileage ( m ) = rate ( mpg ) * gallons ( g ) x gallons is a full tank { 462 = rx { 336 = ( r - 15 ) x solve for r , r = 55 55 - 15 = 40 mpg e"
Answer: E