a train 150 metres long, travelling at 75 km per hour, overtakes another train travelling in the same direction at 45 km per hour. In how many seconds does the first train pass a passenger sitting in the second train ? if the first train passes the second completely in 30 seconds, find the length of the second train.

1) 22 sec, 150 m
2) 10 sec, 50 m
3) 25 sec, 200 m
4) 18 sec, 100 m