A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?

A 40 minutes

B 1 hour

C 1 hr 15 min

D 1 hr 30 min

Correct Answer: Option C

Rate downstream = 1/10 x 60 km/hr = 6 km/hr. Rate upstream = 2 km/hr.

Speed in still water = 1/2 (6 + 2) km/hr = 4 km/hr. Required time = 5/4 hrs = 1 hr 15 min.