Question

A man can row at 8 kmph in still water. If the river flows at 2 kmph, it takes him 48 minutes to row to a place and back. How far is the place from the starting point?

• A. 1 km
• B. 2 km
• C. 3 km
• D. 4 km

Answer 1

The correct option is C 3 km

Let the distance be‘d’. Speed of water flow is 2km/h and speed of man is 8km/h
time to go upstream = $t_1=\frac{d}{(8-2)}h$
time to go downstream = $t_2=\frac{d}{(8+2)}h$
total time, T = $t_2+t_2=48mins$
$d\times (\frac{1}{6}+\frac{1}{10})=\frac{48}{60}h$
therefore, distance = 3km