A man can row at 5 km/hr in still water and the velocity of current is 1 km/hr. It takes him 1 hour to row to a place and back. How far is the place?

Speed downstream = (5 + 1) km/hr = 6 km/hr Speed upstream = (5 - 1) km/hr = 4 km/hr Let the required distance be d km Then, d/6 + d/4 = 1 ⇒ 2d + 3d = 12 ∴ d = 2.4 km