# Easy Time, Speed & Distance Solved QuestionAptitude Discussion

 Q. Rahul can row a certain distance downstream in 6 hour and return the same distance in 9 hour. If the speed of Rahul in still water is 12 km/hr, Find the speed of the stream.
 ✖ A. 2 km/hr ✔ B. 2.4 km/hr ✖ C. 3 km/hr ✖ D. 1.5 km/hr

Solution:
Option(B) is correct

Let the speed of the stream be $x$ km/hr

Thus, downward stream = $(12+x)$

and upward stream = $(12−x)$

suppose the distance travelled be $y$, Given:

$\dfrac{y}{12+x}=6$ and $\dfrac{y}{12-x}=9$

On solving these two equations we get:

$x$ = 2.4 km/hr