Question

A man can row 13 km/hr upstream and 9 km/
he downstream. What will be the speed of
boat in still water
(a) 10 km/hr
(b) 11 km/h
(c) 10.5 km/h
(d) 11.5 km/hr.​

Answer 1

Answer:

10 km per hour is answer

Step-by-step explanation:

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Answer 2

Let the speed of boat in still water be x km/hr

And it's obvious to take the speed of the stream.. Let it be y

Now, speed upstream= x-y

And speed downstream= x+y

But, it is given that, speed upstream =13km/hr

And,speed downstream =9km/hr

Now,we get linear equations,

x-y=13________(a)

x+y=9_________(b)

Now,adding a and B, we get:

x-y+x+y=22

x+x=22. (y canceled)

2x=22

x=11

Hence, the speed of boat in still water is x=11km/hr