Advanced ALgebra!!?

Question

Graham walked to school at an average speed of 3 miles an hour and jogged back along the same route at 5 miles an hour. If his total traveling time was 1 hour, what was the total number of miles in his round trip?

I already know the answer to this question (answer key) I just need to know how to get the answer.

BTW, the answer is NOT 4.
TY in advance.

Answer 1

Here is another approach.

Distance = rate x time

Since d is the same both ways.

r(going) x t(going) = r(returning) x t(returning)

Remember we are working with miles/ hour so our time has to be expressed in hours. Since the whole trip took one hour the time at 3 mph is t and the time at 5 mph is (1-t)

At 3 mph:

3t = 5(1-t)
8t = 5
t = 5/8 of hour
so d = 3(5/8) =1.875 miles

Check it out at 5 mph

5(1 - 5/8) = 15/8 or 1.875 miles

so his round trip was 1.875 * 2 = 3.75 miles
.

Answer 2

Let x be the number of miles between the school and his starting point. If speed is distance divided by time, then time is distance divided by speed. So the time walking to school was x/3, and the time jogging back was x/5 (it was the same distance, only with a different speed). These two times total one hour, so x/3 + x/5 = 1. Solve this for x, and take TWICE that amount for your answer, because the question is how long the ROUND trip was (x is only the distance measured from one point to another, and he crosses this twice).