Math, asked by manikanramachan, 1 year ago

An aeroplane takes 1hour less for journey of 1200km if it's speed is increased by 100 kmhr from its usual speed find the usual speed

Answers

Answered by sk0768173gmailcom
7
let it's original speed be x km/h
ATQ

1200/x -1200/x+100 =1
1/x-1/x+100 =1/1200
x+100-x/x(x+100) =1/1200
100/x(x+100)=1/1200
x^2+100x-120000=0
x^2 -300x+400x-120000=0
x(x-300)+400(x-300)
(x-300)(x+400)

x=-400 (neglecting because speed can't be -ve)
x=300 Ans
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