Question

Ashok can row upstream at $8kmph$ and downstream at $12kmph$. What is the speed of the stream?

• A. 6 km/hr
• B. 3 km/hr
• C. 2 km/hr
• D. 4 km/hr
• E. 4.5 km/hr

Answer 1

The correct option is C 2 km/hr

If the speed downstream is $akmph$ and the speed upstream is $bkmph$
then
Speed of the stream $=\frac{1}{2}(a-b)kmph$
Speed downstream $a=12kmph$
Speed upstream $b=8kmph$
Speed of the stream $=\frac{1}{2}(a-b)=\frac{1}{2}(12-8)$
$=\frac{4}{2}=2kmph$
Speed of the stream = $2kmph$