A sailor goes 8 km downstream in 40 minutes and returns in 1 hour.Determine the speed of the sailor in still water and the speed of the current?

Let the **speed of sailor **in still water be **x km/hr **and the **speed of stream **be** y km/hr.**

The **speed of boat (upstream**) = **(x - y) km/hr.**

The **speed of boat (downstream)** = **(x + y) km/hr.**

Now,

A.T.Q.

(1) 8 / x + y = 40 / 60** (Since, Time = Distance / Speed)**

===> x + y = 12 ----------------- (1)

(2) 8/ x - y = 1 **(Since, Time = Distance / Speed)**

===> x - y = 8 ------------------- (2)

On adding (1) and (2),

===> x ~~+ y~~ + x ~~- y ~~= 12 + 8

===> 2 x = 20

===>__ x = 10__

By (1),

===> 10 + y = 12

===>__ y = 2__

**Ans :- The speed of sailor in still water is 10 km / hr.**

**The speed of stream is 2 km / hr.**

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