posted by Elisa .
A boat moves through the water of a river at 5 m/s relative to the water, regardless of the boat's direction. If the water in the river is flowing at 1.3 m/s, how long does it take the boat to make a round trip consisting of a 215 m displacement downstream followed by a 215 m displacement upstream?
So there are two scenarios:
1. Upstream: speed of boat
: 5m/s - 1.3m/s
2. Downstream: speed of boat: 5m/s+1.3m/s
I then multiplied each by 215m and then added that answer, but I get a really small number. I know I am doing something wrong.
215/(5-1.3) = 58.1sec. upstream
215/(5+1.3) = 34.1 sec. downstream
Round trip time = 92.2 sec.