Walking at 4km/h, Bruce can make the roundtrip between his campsite and Lookout Point in 2.5 h. Rowing on Crooked River, he can row upstream from the campsite to Lookout Point in 1 h and can row back again in 40 min. Find Bruce’s rate of rowing in still water and the speed of the current in Crooked River.

Question

Henry · Answer

t(avg) = (40 + 60) / 2 = 50min = Time required to row the distance in still water.

V = d / t = 5km / 50min = 0.1km/min = = 6km/h in still water.

V = Vmax - Vmin,
V=5km/(2/3)h -5km / 1h=7.5 -5=2.5km/h = speed of stream.