A motor boat whose speed is 24 km/h in still water takes 1hour more to go 32 km upstream than to return downstream to the same spot . find the speed of the stream.
Answers
Answered by
28
Let the speed of the stream be 'x', then ..
32/(24-x) - 32/(24+x) = 1 .....(∵ time = distance/speed )
32(24 + x - 24 + x )/(24-x)(24+x) = 1
64x = 576 - x²
⇒x² + 64x - 576 = 0
On solving the equation, we get
x = (-64 + 80)/2 .....(∵ negative case is not possible)
= 16/2
= 8
∴ The speed of stream is 8 km/h
Hope that helps :)
32/(24-x) - 32/(24+x) = 1 .....(∵ time = distance/speed )
32(24 + x - 24 + x )/(24-x)(24+x) = 1
64x = 576 - x²
⇒x² + 64x - 576 = 0
On solving the equation, we get
x = (-64 + 80)/2 .....(∵ negative case is not possible)
= 16/2
= 8
∴ The speed of stream is 8 km/h
Hope that helps :)
khushi332001:
Thanks
Answered by
3
Answer:
Step-by-step explanation:
Let the speed of the stream be s km/h.
Speed of the motor boat = 24 km/h
Speed of the motor boat upstream = 24-s
Speed of the motor boat downstream = 24+s
According to the given condition,
32/24-s - 32/24+s
32( 1/24-s - 1/24+s ) = 1
32 ( 24+s - 24+s/ 576-s^2 ) = 1
32* 2s = 576-s^2
S^2 + 64s - 576 = 0
S = -72 or s =8
Since, speed of the stream cannot be negative, the speed of the stream is 8 km/h.
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