Question

Kishore started rowing in river Godavari from Bhadrachalam.He rowed certain distance downstream in 15 hours & returned same distance in 22.5 hours. If the river flows at the rate of 7.5 km/hour then find the speed of Kishore in still water.​

Answer 1

Step-by-step explanation:

Let the speed of boat in still water be x

Given that the speed of river is 7.5 km /hr

so speed downstream = (x+7.5)km /hr

speed up stream = (x-7.5)km / hr

Now we know

speed = Distance/ time taken

$(x + 7.5) = \frac{d}{15}$

and

$(x - 7.5) = \frac{d}{22.5}$

since Distance is same

$(x + 7.5) \times 15 = (x - 7.5) \times 22.5$

now

$15x + 7.5 \times 15 = 22.5x - 7.5 \times 22.5$

$7.5x = 7.5(15 + 22.5)$

$x = 30km \: per \: hr \:$

Therefore the speed of still water is 30 km /hr

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