Question

A boy can swim in still water at $1m/s$. He swims across a river flowing at $0.6m/s$ which is $336m$ wide. If he travels in shortest possible time, then what time he takes to cross the river

• A. $420s$
• B. $250s$
• C. $340s$
• D. $336s$

Answer 1

The correct option is D $336s$

Given,

$v_{mr}=1m/s$

Shortest possible time to cross the river is:

$t=\frac{w}{v_{mr}}=\frac{336m}{1m/s}$

$=336s$