Ahsoka Tano travels on a raft upstream for 3 hours and then downstream to her starting point for 1 hour. The speed of the raft is 6 mi/h in still water. What is the speed of the stream’s current?

Answer 1

Going upstream, the current's speed subtracts from the rowing speed and adds to it going downstream. If I can row 2 mph and I'm in a river with a 5 mph current, I'm going to go 7 mph rowing downstream, but I'll also travel 3 mph downstream (backward) trying to row upstream (2 - 5 = -3).

d = rt, and the distances are equal.

3(6 - s) = 1(6 + s)

18 - 3s = 6 + s

-4s = -12

s = 3 mph