Impeded by the current, the outing club took 4 hrs and 24 mins to paddle 11 km up the exeter river to their campsite last weekend. the next day, the current was with them, and it took only 2 hrs to make the return trip to campus. everyone paddled with the same intensity on both days. at what rate would the paddlers have traveled if there had been no current? what was the speed of the current?
distance / rate = time
upriver 11 / (r-c) = 4.4 hr r = speed if paddling in still water c = current speed
re-arrange to c = (11-2r)/2
downriver 11/ (r+c) = 2 sub in the red equation then sovle for r
r = 4 km/hr
Use this result in either of the upstream or downstream equations to find c = 1.5 km/hr
If no current : 11 km / 4 km/hr = 2.75 hrs 2 hrs 45 min