The speed of a boat in still water is 10 km/hr. If it can travel 26 km downstream and 14 km upstream at the same time, the speed of the stream is-

A. 2 km/hr

B. 2.5 km/hr

C. 3 km/hr

D. 4 km/hr

Answer: Option C

Solution(By Examveda Team)

Let the speed of the stream be x km/hr
Then speed downstream = (10 + x) km/hr
Speed upstream
$$\eqalign{ & {\text{ = }}\left( {10 - x} \right)km/hr \cr & \therefore \frac{{26}}{{\left( {10 + x} \right)}} = \frac{{14}}{{\left( {10 - x} \right)}} \cr & \Rightarrow 260 - 26x = 140 + 14x \cr & \Rightarrow 40x = 120 \cr & \Rightarrow x = 3\,km/hr \cr} $$