Question

a boat has speed 5km/h in still water. it crosses a river of width 1 km along shortest path in 15 minutes. Velocity of river is

Answer 1

The boat should only need a speed of 4km/hr to reach 1k in 15 minutes, if the water was still. If the boat continuously travels in a strait line while the water is moving, the boat would need to steer into the current to maintain a strait line to achieve the 1km shortest path. Since the boat speed is 5km, the boat had to speed up 1km/h to 5km/h and steer into the river current.