Two trains 200 meters and 150 meters long are running on parallel rails in the same direction at speed of 40 km/hr and 45 km/hr respectively. Time taken by the faster train to cross the slowed train will be:

A. 72 seconds

B. 132 seconds

C. 192 seconds

D. 252 seconds

Answer: Option D

Solution(By Examveda Team)

Relative speed = (45 - 40) km/hr = 5 km/hr
= $$\left( {5 \times \frac{5}{{18}}} \right)$$  m/sec
= $$\frac{{25}}{{18}}$$ m/sec
Total distance covered = Sum of lengths of trains = (200 + 150) m = 350 m
∴ Time taken
= $$\left( {350 \times \frac{{18}}{{25}}} \right)$$   sec
= 252 seconds