how do i set up the problem

Question

Perry traveled to the town hall and back. It took one hour less time to get there than it did to get back. The average speed on the trip there was 42 mph. The average speed on the way back was 35 mph. How many hours did the trip there take

Answer 1

The average speed is found when you divide the distance by the time.

 

Now, let's say the distance between the original point to the town hall is X. It is the same distance returning back.

 

Let's say The time returning back is T, that means the time spent to hall is T - 1.

 

Then you have the averages to hall and returning back:

 

To hall    42 = X / (T - 1)

 

Back       35 = X / T

 

You only have to solve one equation and replace the value in the other.