Stacy rowed across the lake with her friend Rainey (in the same boat) at a rate of 4 mph. Rainey then rowed back at a rate of 3 mph. If the lake is 6 miles across, how long did it take them to complete their trip?

Question

anonymous · Answer

You use the formula d = rt  
So for the first part of the trip 6 = 4t  because we know the rate is 4 but we don't know how long it took. If you divide both sides by 4 you will get 1.5 = t

The second part is 6 = 3t because we know the rate is 3 but we don't know how long it took.  If you divide both sides by 3 you will get 2 = t.

So it took you 1.5 hours for the first half and then 2 hours to get back fo a total of 3.5 hours.