DIRECTIONS for questions 7 to 10: The questions are based on the following information.
There are three parallel tracks of 120 km between X and Y.
Train A starts at 9 am on the central track at 60 kmph from X.
Train B starts at 10 am at 60 kmph from Y.
Train C starts at 11 am at 90 kmph from X.
Train A and C are 100 m each and train B is 150 m long.
The total time, when B was crossing the two trains was