Math, asked by sohelgora7275, 1 year ago

A boat covers 25 km upstream and 44 km downstream in t hours. Also, it covers 15 km upstream and 22 km downstream in 5 hours.

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Answered by Anonymous
6


Secondary SchoolMath5 points

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 boat in still water and that of the stream

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Ask for details FollowReport byGeethikasajeev 10.09.2017

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AishwaryaSunilAmbitious

Speed of boat in still water=x km/hr
Speed of stream=y km/hr
Speed of upstream=x-y km/hr
Speed of downstream=x+y km/hr
Let 1/(x-y)=a and 1/(x+y)=b
Time to go 25km up and 44 down=9
25a+44b=9----->(1)
Time to go 15km up and 22km down=5
15a+22b=5------>(2)
(2) × 2=> 30a+44b=10------>(3)
(3)-(1)=>5a=1
a=1/5
1/(x-y)=1/5
x-y=5---->(4)
Putting a=1/5 in (1),
5+44b=9
44b=4
b=1/11
1/(x+y)=1/11
x+y=11---->(5)
(4)+(5)=>2x=16
x=8
y=3
Speed of boat in still water=8km/hr
Speed of stream=3km/hr

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