Question

Ram can row downstream $20km$ in $2$ hours and upstream $4km$ $2$ hours. Find his speed of rowing in still water and speed of current.

Answer 1

Let $x$ and $y$ be the speed of Ram in still water and speed of stream repectively.

Therefore,

Speed of Ram while rowing downstream $=(x+y)km/hr$

Speed of Ram while rowing upstream $=(x-y)km/hr$

Now, according to the question-

$x+y=\frac{20}{2}$

$\Rightarrow x+y=10.....\left(1\right)$

Also,

$x-y=\frac{4}{2}$

$\Rightarrow x-y=2.....\left(2\right)$

Adding equation $\left(1\right)\&\left(2\right)$, we have

$(x+y)+(x-y)=10+2$

$2x=12$

$\Rightarrow x=\frac{12}{2}=6km/hr$

Substituting the value of $x$ in equation $\left(1\right)$, we have

$6+y=10$

$\Rightarrow y=10-6=4km/hr$

Hence the speed of Ram in still water is $6km/hr$ and the speed of current is $4km/hr$.