Question

On the trip from Detroit to Columbus, Ohio, Mrs. Smith drove an average speed of 60 mph. Returning, her average speed was 55 mph. If it took her 1 3 of an hour longer on the return trip, how far is it from Detroit to Columbus?

Answer 1

Let 
 D = distance between Detroit and Columbus 
 From Detroit to Columbus, 
 D = 60T1 
 where 
 T1 = time it took Mrs Smith to drive from Detroit to Columbia 
 From Columbia to Detroit
 D = 55T2 
 where 
 T2 = time it took Mrs Smith to drive from Columbia to Detroit
 Equating the 2 formulas for "D", 
 60T1 = 55T2 
 and since T2 = T1 + 0.33
 60T1 = 55(T1 + 0.33)
 Solve for T1 and substitute this calculated value in the equation D = 60T1 to determine the distance between Detroit and Columbus.
 5T1=18.15
 T1= 18.15/5=3.63
 then 
 D = 60T1=60*(3.63)=217.8 m