Question

A train travels 480 km at a uniform speed. If the speed had been 10km/h more, it
would have taken 4 hours less for the same journey, find the speed of the train?​

Answer 1

Answer:

Step-by-step explanation:

480/x-4 -480/x = 10

480x-480x+1920=10x*2-40x

(10x*2-40x-1920=0) ÷10

x*2-4x-192=0

x*2-16x+12x-192=0

x(x-16)+12(x-16)=0

(x-16) (x+12)=0

x-16=0 x+12=0

x=16 x= -12

Answer 2

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.