Question

The velocity of a boat in a river of width 1.0 km is 5 km/h. The boat crosses the river in 15 minutes, moving over the shortest path. Hence the velocity of the flow of river is ............ km/h.
(A) 1
(B) 3
(C) 4
(D) 5

Answer 1

Velocity= distance /time

             = 1km /0.25 hr. ......(15 min=0.25hrs)

             = 4 km/hr  

The velocity of the river water is 4 km/hr

thanks