28. A train travelling at 36 kmph completely crosses another train having half its length and travelling in the opposite direction at 54 kmph, in 12 seconds. If it also passes a railway platform in 1 minutes, the length of the platform is:

29. Two trains are running on parallel lines in the same direction at a speed of 50 km and 30 kim per hour respectively. The faster train crosses a man in slower train in 18 seconds. The length of the faster train is:

30. Two trains A and B star from station X and Y toward Y and X respectively. After passing each other, they take 4 hours 48 minutes and 3 hour 20 minutes to reach Y and X respectively. If train A is moving at 45 km/hr. then the speed of train B is: