Q. 24.0( 3 Votes )

# A boat covers 25 km upstream and 44 km downstream in 9 hours also it covers 15 km upstream and 22 km downstream in 5 hours. Find the speed of the boat in still water and that of the stream.

Answer :

Let the speed of the boat in still water and speed of stream be a km/hr & b km/hr respectively.

__In case of upstream;__

Speed = speed of boat – speed of stream = a – b

__In case of downstream;__

Speed = speed of boat + speed of stream = a + b

As, distance = speed x time,

According to the question,

Eqn (i) – 2 × eqn (ii)

⇒ a – b = 5 ...... (iii)

Putting this in equation (i);

⇒ a + b = 11 ...... (iv)

Now solving equation (iii)&(iv) by adding:

2a = 16

a = 8

b = 3.

So, the speed of the boat in still water is 8 km/hr

and the speed of the stream is 3 km/hr.

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