Question

A boat which has speed of 8 km/h in still water crosses the river with a velocity of 7 km/h along the

shortest path. The velocity of the river in km/h is​

Answer 1

Answer:

Explanation:

Shortest possible path,s=1km

Time taken, t=15min=0.25hr

Speed in the direction of shortest path,

t s =  v 2 −u 2

Where, v=5kmh −1

velocity of boat, u velocity of river.

t s = v 2 −u 2 0.25 1 = 5 2 −u 2

u=3kmh −1

Hence, velocity of river is 3kmh −1