Question

A train running at the speed of 20m/s crosses a pole in 24 seconds less than the time it requires to cross a platform thrice its length at the same speed. What is the length of the train? (

Answer 1

Let length of train is L

and Let time taken by train to cross the platform of length 3L is T.

we know, speed = distance/time

so, speed of train = (length of train + length of platform)/time taken

or, 20 = (L + 3L)/T

or, 20 = 4L/T

or, T = L/5 ........(1)

again, train crossed a pole with speed 20 m/s in 24 sec less than the time T .

so, time taken by train to cross a pole = length of train /speed of train

or, T - 24 = L/20

from equation (1),

or, L/5 - 24 = L/20

or, L/5 - L/20 = 24

or, 3L/20 = 24

or, L = 160m

hence, length of train = 160m

Answer 2

Answer:

Refer to the above answer

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