Question

A man can row at 5 kmph in still water. If the velocity of current is 1 kmph and it takes him 1 hour to row to a place and come back, how far is the place?

• A. 2.4 km
• B. 2.5 km
• C. 3 km
• D. 3.6 km

Answer 1

The correct option is A 2.4 km

Speed downstream $=(5+1)kmph=6kmph$
Speed upstream $=(5-1)kmph=4kmph$
Let the required distance be x km.
Then, $\frac{x}{6}+\frac{x}{4}=1$
$\Rightarrow 2x+3x=12$
$\Rightarrow 5x=12$
$\Rightarrow x=2.4km$