Due to some technical problems an aeroplane started late by one hour from its starting point.The pilot decided to increase the speed of the aeroplane by 100 km/hr from its usual speed to cover a journey of 1200 km in time.Find the usual speed of the aeroplane.(the answer is 300 km/hr) plzz give the solution for this problem...
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let the usual speed of the plane be x kmph
so time taken to reach the destination= 1200/x
due to glitch, it had to increase its speed by 100 kmph
so time taken by the plane= 1200/(x+100)
time difference=1
so (1200/x)-1200/(x+100)=1
1200(x+100-x)=x(x+100)
1200(100)=x(x+100)
(x^2)+100x-120000=0
(x^2)+400x-300x-120000=0
x(x+400)-300(x+400)=0
(x-300)(x+400)=0
x=300
so time taken to reach the destination= 1200/x
due to glitch, it had to increase its speed by 100 kmph
so time taken by the plane= 1200/(x+100)
time difference=1
so (1200/x)-1200/(x+100)=1
1200(x+100-x)=x(x+100)
1200(100)=x(x+100)
(x^2)+100x-120000=0
(x^2)+400x-300x-120000=0
x(x+400)-300(x+400)=0
(x-300)(x+400)=0
x=300
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