A person goes 15 km downstream in 3 hrs and return upstream in 5 hours. Find the speed of boat in still water(in km/hr).

4

Speed of boat in downstream (D.S) = \(\frac{15}{3}\) = 5 km/hr

Speed of boat in upstream (U.S) = \(\frac{15}{5}\) = 3 km/hr

Speed of boat in still water = \(\frac{D.S\;+\;U.S}{2}\) = \(\frac{5\;+\;3}{2}\) = \(\frac{8}{2}\) = 4 km/hr