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A person reaches on a point directly opp...

A person reaches on a point directly opposite on the other bank of a river.The velocity of the water in the river is `4 m//s`and the velocity of the person in still water is `5 m//s`.If the width of the river is `84.6m`, time taken to cross the river in seconds is

A

`28.2`

B

`9.4`

C

2

D

`84.6`

Text Solution

Verified by Experts

The correct Answer is:
A
Given, velocity of water `upsilon_(w)=4 ms^(-1)`
Velocity of person `upsilon_(p)=5 ms^(-1)`, width of the river `= 84.6 m`
We know that time taken, `t=(s)/(sqrt(upsilon_(w)^(2)-upsilon_(p)^(2)))`
`rArr t=(84.6)/(sqrt(25-16))`
`rArr t=(84.6)/(3)~=28.25`
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