Question

A train of length 450m crosses a pole with a speed of 72km/h .How long will it take to cross the pole .​

Answer 1

Hey Buddy ! ☺

Length of pole = 450m
$speed \: of \: train = 72km/h \\ = 72 \times \frac{5}{18} m/sec \\ = 20m/sec \\ \\ Now;\\ \\ speed = \frac{dist}{time} \\ \: \\ = > time = \frac{dist}{speed} \\ \\ = > time = \frac{45 \cancel0}{2 \cancel0} \\ \\ = > time = \frac{45}{2} sec \\ \\ = > \fbox{time = 22.5 \: sec}$