Question

Explain it also by easy techniques

Answer 1

opinion 4 because
river speed = 3 km/h
speed of Man = 4km/h
4-3= 1km/hr
so 1km = 1000m

Answer 2

Answer

Option D

750m

Since he makes his stroke normal to river current, the movement of river will have no effect,

$Time will be \: \: T = \frac{Distance }{Speed } = \frac{ 1 }{4} hr$

$0.25hr = 15min$

In the same time he will go down

Distance = speed x time = 3km/hr X

0.25hr = 0.75 km = 750m