Question

a train covers a distance of 90km at a uniform speed.had the speed been 15km/hr more it would have been 30mins less for the journey find the original speed of the train

Answer 1

Answer:

60km/hr

Step-by-step explanation:

Train going at 45km/hr makes the journey of 90km in 2hrs. At 60km/hr the journey will take 1.5hrs

Answer 2

Step-by-step explanation:

Let that speed of the train be x km/h

so,time taken=90/x

so,if the speed of the train had been 15km/h more=x+15

30 minutes =1/2hr

so, ATQ

x+15=90/x-1/2

=x+15=180-x/2x

=2x(x+15)=180-x

=2x^2+30x-180+x=0

=2x^2+31x-180=0

=2x^2+40x-9x-180=0

=2x(x+20)-9(x+20)=0

=(2x-9)(x+20)=0

so, speed of train= 2x - 9=0

2x=9x=9/2=45km/h