Question

A boat travels 30 miles upstream in 5 hours. The return trip downstream takes 3 hours. If the boat travels at the same rate on both parts of the trip, what is the rate of the current, in miles per hour?

Answer 1

5(v-s)=30 and 3(v+s)=30

5v-5s=30

v-s=6

v=6+s now use this v in the second equation from the beginning...

3(6+s+s)=30

6+2s=10

2s=4

s=2 and since v-s=6, v=6+s=8

So the rate of the boat is 8mph and the rate of the current is 2mph