Question

Speed of a boat is 5 km per hour in still water and the speed of the stream is 3 km per hour. If the boat takes 3 hours to go to a place and come back, the distance of the place is :

• A. 3.75 km
• B. 4 km
• C. 4.8 km
• D. 4.25 km

Answer 1

Answer:

C. 4.8 km

Let the required distance be x km, then

$\frac{x}{5+3}+\frac{x}{5-3}=3$

$\frac{x}{8}+\frac{x}{2}=3$

$\frac{x+4x}{8}=3$

$5x=24$

$x=\frac{24}{5}=4.8 km$