Question 236369
We use the equation distance/time = speed. Rearranged is distance/speed = time.

D/S = T

We travelled north 5 miles in speed that is 6 mph more than we travelled south. So we can say:

5/(x+6) 

Where x is the unknown speed.

We travelled south at x speed:

3/x

Now because we know that the time taken to travel these two distance was the same we can say these two equations equal each other:

5/(x+6) = 3/x

So we need to rearrange to get x on its own:

5x/(x+6) = 3

5x = 3x+18

2x = 18

x = 9

So the speed going north was 15 mph, speed going south was 9mph. Time going north was 5 miles divided by 15 mph = 1/3 hour or 20 minutes which is the same time going south.

Does that help?

Make any sense?