Q 11-02-126JEE MainJEE Main 2019 (12 Jan, Shift 1)Easy
A passenger train of length $60$ m travels at a speed of $80$ km/hr. Another freight train of length $120$ m travels at a speed of $30$ km/hr. The ratio of times taken by the passenger train to completely cross the freight train when: (i) they are moving in the same direction, and (ii) in the opposite directions is:
Answer: (C) $\dfrac{11}{5}$
The distance to be covered relative to the freight train is $60 + 120 = 180$ m in both cases.
Relative speeds: same direction $80 - 30 = 50$ km/h; opposite directions $80 + 30 = 110$ km/h.
$$\frac{t_1}{t_2} = \frac{110}{50} = \frac{11}{5}$$
Solution by Sreeraj P, M.Sc Physics