Question

A train travels at a distance of 480 km at a uniform speed. If the speed had been 8 km per hour less then it would have taken 3 hours more to cover the same distance. We need to find the speed of the train ​

Answer 1

Answer:

after the last line do middle term factorization and u will get the answer

Answer 2

Answer:

40km/hr

Step-by-step explanation:

distance =480km

let the speed be x

and time be t

speed = distance /time

x=480/t

same as ,t=480/x ......................(1)

also,

x-8=480/(t+3).......................(2)

substitute t with (1) in (2)

x-8=480/(480/x+3)

(x-8)(480/x+3)=480

480 +3x -3840/x -24=480

3x -3840/x -24=0

3x^2-3840-24x=0

x^2-8x-1280=0

x^2-40x+32x-1280=0

x(x-40)+32(x-40)=0

(x-40)(x+32)=0

x=40 or x= -32

x can't be negative so x =40km/hr