shows less than the first for the same jumes, find the length of the fourmet . Abus covers a certain distance in minutes if at runs at a speed of 50 lmht. What must be the speed of the bus in order to reduce the time of the joumey to 30 minutes?
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Answer:
Uniform speed =x km/h
distance =240 km
time =
Speed
Distance
=
x
240
hours
Due to heavy rain speed =(x−10) km/h
Now time =
x−10
240
hours
According to question
x−10
240
−
x
240
=2
x(x−10)
240x−240(x−10)
=2
x
2
−10x
240x−240x+2400
=2
⇒2x
2
−20x−2400=0
⇒x
2
−10x−1200=0
x
2
−40x+30x−1200=0
x(x−40)+30(x−40)=0
⇒(x−40)(x+30)=0
x=40 and x=−30 (speed can not be negative)
∴ uniform speed =40 km/h.
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