Question

Two trains are each $50m$ long moving parallel towards each other at speeds $10m/s$ and $15m/s$ respectively. After what time will they pass each other?

• A. $5\sqrt{\frac{2}{3}}sec$
• B. $4sec$
• C. $2sec$
• D. $6sec$

Answer 1

The correct option is B $4sec$

As both the trains are moving in the opposite direction, the relative speed of each train with respect to each other be, $v=10+15=25m/s$

Here distance covered by each train = sum of their lengths $=50+50=100m$

$\therefore$ Required time$=\frac{100}{25}=4sec$