Question

The speed of a swimmer is $4 km h ^{-1}$ in still water If the swimmer makes his strokes normal to the flow of river of width $1 km$, he reaches a point $750 m$ down the stream on the opposite bank.The speed of the river water is ___ $km h ^{-1}$

Answer 1

The correct answer is 3

time to cross the River width ω=1000m
is =4km/h1km​
Drift x=Vm/g×t
Where Vm/g is velocity of River w.r. to ground.
x=Vm/g×41​=750m=43​km
Vm/g=3km/hr