Two trains having lengths of 370 m and 330 m are running at speeds of 90 km/h and 150 km/h, respectively, in the same direction. The time taken (in minutes) by the faster train, coming from behind, to completely cross the other train is:

Correct option is D

Given:

Length of first train = 370 m

Length of second train = 330 m

Speed of first train = 90 km/h

Speed of second train = 150 km/h

Concept Used:

$$\text{Relative Speed} = \text{Speed of faster train} - \text{Speed of slower train}\\ \ \\\text{Time} = \frac{\text{Sum of train lengths}}{\text{Relative speed}}$$​

Solution:

Length of both train = 370 + 330 = 700  

Both train, same direction that's why Difference = 150 - 90 = 60 km/hr 

​Total = $$\frac{\text{Total Distance }}{\text{Total time}}\times\frac{18}5$$​    

= $$\frac{700}{60}\times\frac{18}5 = 42 sec$$​

1 min = 60 sec
42 sec = $$\frac{42}{60} = 0.7 min$$​​