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MOYANSARAHIN
Answered

3. The boat travels 30 km up a river in the same time it takes to travel 50 km down the
same tiver. If the current of water is 5km/hr. what is the speed of the boat in still
water?​

Sagot :

REIYUJI450IN

Answer:

Let speed of boat in still water=B km/hr

And given speed of water=5 km/hr

Speed of boat upstream=B-5 km/hr

Speed of boat downstream= B+5 km/hr

So

Using the formula time=distance/speed

Time taken to travel 30 km upstream t1= 30/(B-5)

Time taken to travel 50 km downstream= 50/(B+5)

Given t1=t2

30/(B-5)=50/(B+5)

=> 3/(B-5)=5/(B+5)

=> 3(B+5) = 5(B-5)

=> 3B+15 = 5B+25

=> 40=2B

=> B=20 km/hr

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