A man can swim with a speed of 4 km/h in still water. How long does he take to cross a river 1 km wide if the river flows steadily at 3 km/h and he makes his strokes normal to the river current? How far down the river does he go when he reaches the other bank?

Asked by Pragya Singh | 1 year ago |  101

##### Solution :-

Speed of the man $$v_m$$ = 4 km/h

Width of the river = 1 km

Time taken to cross the river = $$\dfrac{Width \; of \; the \; river }{Speed \; of \; the \; river}$$

$$\dfrac{1}{4}h=\dfrac{1}{4}\times 60 = 15\; min$$

Speed of the river,$$v_r$$ = 3 km/h

Distance covered with flow of the river = vr × t

$$3 \times \dfrac{1}{4}=\dfrac{3}{4}$$

$$\dfrac{3}{4} \times 1000=750 \;m$$

Answered by Abhisek | 1 year ago

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