Question

A boat travels upstream and after one hour has gone 10 km. the boat next travels downstream and after one hour has gone 18km. if the boats speed relative to the water is constant, what is the speed of the river

Answer 1

4 km/h

Step-by-step explanation:

Let the boat's speed relative to the water be u and the speed of the water be v (both in km/h)

upstream: boat's speed = u - v

during t = 1 hour, the distance is (u - v) * 1 = 10 (1)

downstream: boat's speed = u + v

during t = 1 hour, the distance is (u + v) * 1 = 18 (2)

(2) - (1): 2v = 18 - 10 = 8, so v = 4 km/h