Query Detail : RBI Grade B Phase I

The boat takes total time of 4 hours to travel 14 km upstream and 36 km downstream together. The boat takes total time of 5 hours to travel 20 km upstream and 24 km downstream together? Speed of the boat inn still water (in km/h).
Garima,   November 6th 2019,  
RBI Grade B Phase I


Let U = speed of boat in still water & V = speed of water

14/(U-V) + 36/(U-V) = 4

and 20/(U-V) + 24/(U+V) = 5

Solve these equations, find U.