A boat moves 25 km upstream and 39 km downstream in 8 hours. It travels 35 km upstream and 52 km downstream in 11 hours. What is the speed of the stream if it travels at a uniform speed?

Solution (By Examveda Team)

Let speed of boat is x and stream is y km/hr
According to the question
$$\eqalign{ & \frac{{25}}{{x - y}} + \frac{{39}}{{x + y}} = 8 \cr & \frac{{35}}{{x - y}} + \frac{{52}}{{x + y}} = 11 \cr} $$
By hit and trail method x = 9, y = 4 it satisfy the both equations
Speed of stream = 4 km/hr