Question

The express train from Addington to Summit travels the 18 -mile route at an average speed of 72 mi./hr., stopping only in Summit. The local train stops for 1.5 minutes at each of the 6 stops between these two locations, and it averages 54 mi./hr. while it is in motion. How many minutes more does the local train take for this trip than the express train?

Answer 1

Express train travel time: 
72x = 18
x = 18/72 = 1/4, or 0.25 hours. A quarter of an hour is 15 minutes
x = 15 minutes

Local Train Travel time: 
54x = 18
x = 18/54 = 1/3 hour, or 20 minutes
Adding the stops: 1.5 * 6 = 9 additional minutes
Total Travel time: 20 + 9 = 29 

Local train takes 29 - 15 = 14 minutes longer.
Answer is 14 minutes