A train 150 m long takes 10 seconds to pass completely another train 100 m long coming from the opposite direction. If the speed of the first train is 30 km/hr, what is the speed of the second train?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 60 km/hr
When two trains pass each other, together they cover the sum of their lengths. Moving in opposite directions, they close the gap at the sum of their speeds.
Sum of the lengths \(=150+100=250\) m
Relative speed \(\displaystyle =\frac{250}{10}=25\) m/s \(\displaystyle =25\times\frac{18}{5}=90\) km/hr
Speed of the second train \(=90-30=60\) km/hr