Question

Kunal takes twice as longs a to row up as to row down. if the rate of stream is 6km/h find the speed of kunal in still water

Answer 1

let "d" is the distance traveled upstream and downstream.

V = speed of kunal

v = speed of water = 6 km/h

V - v = speed in upstream direction

V + v = speed in downstream direction

t₁ = time taken during upstream = d/(V - v)

t₂ = time taken during downstream = d/(V + v)

it is given that

time of upstream = 2 x time of downstream

t₁ = 2 t₂

d/(V - v) = 2d/(V + v)

V + v = 2 V - 2v

V = v + 2 v

V = 3 v

V = 3 x 6

V = 18 km/h