Question

A man can row at 5 km/hr in still water . If the river is running at 1km/hr it takes him 75 minutes to row to a place and back How far is the place ?
A. 2.5 km
B. 3 km
C. 4 km
D. 5 km

Answer 1

Correct Answer - B
Speed of boat in still water = 5 kmph
Speed of stream = 1 kmph
Let distance is x km
`(x)/(5 + 1) + (x)/(5-1) = (75)/(60)`
`implies (5x)/(12) = (5)/(4)`
`implies x = 3` km