Question

A man can row 40 kmph in still water and the river is running at 10 kmph. If the man takes 2 hr to row to a place and back, how far is the place?

• A. 38 km
• B. 37.5 km
• C. 40.75 km
• D. None of these

Answer 1

Answer:

B. 37.5 km

Explanation: 

Given u=40 , v=10

D $= t[\frac{(u2-v2)}{2u}]$

$=2\times{[\frac{(402-102)}{2}\times{40}]}$

$=2\times{(1600-100)}{80}$

$2\times{\frac{1500}{80}}$ ==> 37.5km