1. The problem statement, all variables and given/known data A tugboat releases a barge and continues down the river for t = 64 min. Then it returns and finds the barge 3.9 km downstream from its initial position. Assuming that the speed of the tugboat was constant with respect to the water, the speed of the river is (in km/h) 2. Relevant equations Relative Velocity ~~~ I think Vtw = Vtb + Vbw tugboat wrt water (tw) tugboat wrt barge (vb) barge wrt water (bw) 3. The attempt at a solution I thought the speed of the river would be velocity of barge wrt water? except even that was true...i have no idea what to do with the information given Looking for anything to point me in a starting direction. Not really sure where to start.