Question

Hello guys please help me to solve this sum don't spam!!!!!! step by step explanation those who will solve it in a better way will be marked as the brainliest.​

Answer 1

Answer:

40 km/hr

Step-by-step explanation:

Given, Speed of the express train = x km/hr.

Then the speed of ordinary train = (x - 8) km/hr.

Distance traveled by both the trains = 480 km.

∴ Time = Distance/Speed.

Time taken by the express train = (480/x)

Time taken by the ordinary train = (480/x - 8).

According to the given contention,

⇒ [480/x - 8] - [480/x] = 2

⇒ 480[x - x + 8/x(x - 8)] = 2

⇒ 3840 = 2(x² - 8x)

⇒ 2x² - 16x - 3840 = 0

⇒ x² + 8x - 1920 = 0

⇒ x² + 48x - 40x - 1920 = 0

⇒ x(x + 48) - 40(x + 48) = 0

⇒ x = 40,-48{Speed cannot be negative}

⇒ x = 40.

Therefore, Speed of the express train = 40 km/hr.

Hope it helps!

Answer 2

Let x=speed of express train

x-12=speed of slower train

travel time=distance/speed

..

240/(x-12)-240/x=1

LCD: x(x-12)

240x-240x+2880=x^2-12x

x^2-12x-2880

(x+48)(x-60)=0

x=-48(reject x>0)

or

x=60

ans:

Speed of the express train=60 km/hr