SOLUTION: if the speed of an aeroplane is reduced by 40km per hr,it takes 20 minutes more to cover 1200km. find the speed of the aeroplane.

Question 1084695: if the speed of an aeroplane is reduced by 40km per hr,it takes 20 minutes more to cover 1200km. find the speed of the aeroplane.
Found 2 solutions by Boreal, MathTherapy:
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
speed*time=distance
x is base speed of plane
x*t=1200
(x-40)(t+(1/3))=1200
so xt=xt+(1/3)x-40t-40/3
0=(1/3)x-40t-40/3; x=1200/t
0=(400/t)-40t-(40/3)
multiply by 3t
0=1200-120t^2-40t
120t^2-40t-1200=0
3t^2-t-30=0
(3t-10)(t+3)=0
t=10/3 hours, only positive root.
x*10/3=1200
10x=3600
x=360 km/h, ANSWER, and it will take 3 1/3 hours to go 1200 km
x-40=320 km/h, and it will take 3 2/3 hours (20 more minutes) to go 1200 km.

Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

if the speed of an aeroplane is reduced by 40km per hr,it takes 20 minutes more to cover 1200km. find the speed of the aeroplane.

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