The speed of boat in still water is 11 kilometre per hour and the speed of the stream is X kilometre per hour find in terms of x the speed of boat upstream and the speed of boat downstream If the boat takes 11/4 hour to go 12 kilometre upstream and then Return find the value of x

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Answers

2016-03-04T20:06:06+05:30
Speed of boat downstream=(11+X)km/h
speed of boat upstream=(11-X)km/h
Let t₁ be the time for upstream and t₂ for downstream
t₁=6/(11-X) and t₂=6/(11+X)
(Distance covered in going upstream and downstream is the same)
t₁+t₂=11/4
6/(11-X)+6/(11+X)=11/4
66+6X+66-6X/(121-X²)=11/4
132/121-X²=11/4
528=1331-11X²
11X²=1331-528
11X²=803
X²=73
X=(√73)km/h
X=8.54km/h
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2016-03-04T20:12:26+05:30
Answer will be 5 as the boat cover 24 km in total upstream and down stream....
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