A train is moving with a constant velocity of `18 km//hr`. It crosses a bridge of length `54 m`. The length of train is `36 m`. The choose the correct option(s):

Options

A. (a)The time taken by the train to cross the bridge completely strating from the instant the engine enters the bridge upto the time when whole train has get down of the bridge is `18` seconds.
B. (b)The time taken by the train to cross the bridge completely starting from the instant the engine enters the bridge upto the time when whole train has get down of the bridge is `5` seconds.
C. (c)The time taken by the engine of the train to travel only the length of bridge is `3` sec
D. (d)The time taken by the engine of the train to travel only the length of bridge is `(54)/(5)` sec

Answer

A, D

Explanation

`v = 18 km//hr = 5 m//s`
`l = l_(1) + l_(2) = 36 + 64 = 90m`
`t = (l)/(v) = (90)/(5) = 18 sec`