Question 59

The speed of a boat in still water is 6 km/h. Time taken by the boat to cover a certain distance upstream is 3 hours more than the time taken to cover the same distance downstream.If the speed of the stream is 2 km/h, then what is the total distance, upstream and downstream, covered by the boat?

Solution

Let the speed of the boat be x $$\frac{km}{hr}$$ and speed of stream be y $$\frac{km}{hr}$$.

Let the distance covered in one way be D km.

From the question we have,$$\frac{D}{x+y}$$ + 3 = $$\frac{D}{x-y}$$,

Given,x = 6 $$\frac{km}{hr}$$ and y = 2 $$\frac{km}{hr}$$

we get,$$\frac{D}{4}$$ - $$\frac{D}{8}$$ = 3

i.e.D = 24 km

So,the total distance in upstream and downstream is 24+24 = 48 km

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