Question

Solve the question number 2

Answer 1

Suppose the usual speed of goods train is =x km/hr

Decrease speed of train =x-5 km /hr

Time taken to travel 400km.

Time taken to travel 400km distance with usual speed=400/x=t¹

Time taken to travel 400km distance with decreased speed =400/x-5 =t²

T²-T¹=4(hrs)

400/x-5- 400/x=4x(x-5)

400x-2000- 400x =4x²-20x

4x²-20x+2000

X²-5x+500

(x-25)(x+20)

X=25 OR x=-20 ( speed cannot be negative)

So the usual speed of goods train is 25 km/hr

Decrease speed of train is x-5=25-5+20 km/hr.

Answer 2

Usual speed of goods train is 25 km/hr.