Correct Answer - Option 4 : 14 km/hr
Given
Speed upstream = 8 km/h
Speed downstream = 20 km/h
Formula Used
If speed of a boat in still water is u km/h and the speed of the stream is v km/h. Then,
Speed upstream = (u - v)km/h
Speed downstream = (u + v) km/h
Calculation
Let the speed of the man in still water be u km/h and speed of the stream be v km/h.
According to the question,
⇒ u + v = 20 ……………………………(1)
And u – v = 8 …………………..(2)
Solving both the equations, we get,
⇒ u = 14 km/h
∴Speed of man in still water is 14 km/h.
