A train 360 m long is running at a speed of 45 km/hr. In what time it will it pass a bridge 140 m long?

A.  40 sec   
B.  42 sec
C.  45 sec   
D.  48 sec
Answer: A

Explanation:

speed    =(45 + 5 / 18)m/sec
             =(25 / 2)m/sec
Total distance covered    =(360 + 140 )m
                                     =500 m
Required time    =(500 x 2 / 25)sec
                         = 40 sec.