A man rows 24 km upstream in 6 hours and 36 km downstream in 6 hours each time, then the speed of the boat in the still water is

5 km/hr

The correct answer is Option (1) → 5 km/hr **

Upstream speed = $\frac{24}{6} = 4$ km/h

Downstream speed = $\frac{36}{6} = 6$ km/h

Speed of boat in still water = $\frac{4 + 6}{2} = 5$ km/h

The speed of the boat in still water is 5 km/h.