Q15. A man rows a certain distance along the stream and against the stream in 1 hour and 1.5 hours respectively. If the velocity of the current is 3 km/hr, what is the speed of a man in still water?

A. 15 km/hr

B. 12 km/hr

C. 13 km/hr

D. None of these

Answer- Option A

Explanation-

Let the speed of a man in still water be x km/hr
Speed downstream = (x + 3)km/hr
Speed upstream = (x - 3)km/hr

3

2

(x - 3)

=

1

(x + 3)

x = 15 km/hr
Hence, the spped of a man in still water is 15 km/hr