a train travels 450km at an uniform speed if the speed had been 10km per hour more ,it would have taken 4 hours less for the same

1 thought on “a train travels 450km at an uniform speed if the speed had been 10km per hour more ,it would have taken 4 hours less for the same”

1. Answer:

   Let the speed of the train be x km/hr. Then

   Time taken to travel a distance of 480km=

   x

   480

   hr

   Time taken by the train to travel a distance of 480km with the speed (x−8)km/hr=

   x−8

   480

   hr

   It is given that if the speed had been 8km/hr less, then the train would have taken 3 hours more to cover the same distance

   ∴

   x−8

   480

   =

   x

   480

   +3

   ⇒

   x−8

   480

   −

   x

   480

   =3⇒

   x(x−8)

   480(x−x+8)

   =3⇒

   x(x−8)

   480×8

   =3

   ⇒3x(x−8)=480×8⇒x(x−8)=160×8⇒x

   2

   −8x−1280=0

   This is the required quadratic equation

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