Question

A train 100 m long travelling at 40 m/s starts overtaking another train 200 m long travelling at 30 m/s. The time taken by the first train to pass the second train completely is:

• A. 30 s
• B. 40 s
• C. 50 s
• D. 60 s

Answer 1

The correct option is A 30 s

Relative velocity of overtaking $=40-30=10m/s$
Total relative distance covered with this relative velocity during overtaking
$=100+200=300m$
So, time taken $=\frac{300}{10}=30s$