Question

a train 120 metres long passes a tree in 5 sec. How long will it take to cross a railway platform 180 metres long?​

Answer 1

Step-by-step explanation:

Because, 120 metres long train passes a tree in 5 sec.

$\therefore \: speed \: of \: train = \frac{120}{5} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 24 \: m {s}^{ - 1} \\ length \: of \: platform = 180 \: m \\ \therefore total \: length = 120 + 180 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 300 \: m \\ now \\ time = \frac{distance}{speed} \\ \: \: \: \: \: \: \: \: \: \: \: \: = \frac{300}{24} \\ \: \: \: \: \: \: \: \: \: \: \: \: = 12.5 \: s$

Hence, time taken by the train to cross the platform is 12.5 seconds.