Question

$\large\red{\frak{Question}}$
A person standing on a railway platform, noticed that a train took 21 seconds to completely cross the platform which is 84 m long and it took 9 seconds in crossing him. The speed of the train is
A-25.2 km/h
B-32.4 km/h
C-50.4 km/h
D-75.64 km/h​

Answer 1

Answer:

Correct option is A)

Let the length of the train be x metres 

Then Speed of he train in passing through he platform 21x+84 m/sec

and speed of the train in passing the man = 9x m/sec.

Since both the speeds are the same,

21x+84=9x

⇒9x+756=21x

⇒12x=756

⇒x=12756=63 m

∴ speed of the train = 21(63+84) m/sec =7 m/sec = 7×518 km/hr =25.2 km/hr

Answer 2

Step-by-step explanation:

A ) 25.2 is ur answer

hope i help u

it's Isha