Question

A man can row 14 km/h in still water. In the stream following with the speed of 10 km/h he takes 4 hours to move with the stream and come back.Find the distance he rowed thw boat.

• A. $11.71$ km
• B. $13.71$ km
• C. $14.71$ km
• D. $12.71$ km

Answer 1

The correct option is B $13.71$ km

Let Distance be =D
Speed in upstream$=14-10=4$ km/hr
Speed in downstream$=14+10=24$
Time $=\frac{D}{S}$
According to question
$\frac{D}{4}+\frac{D}{24}=4$
$\frac{7D}{24}=4\Rightarrow =\frac{96}{7}=13.71km$