Answers: 45 Seconds and 129.6 km/h
To find the 45 seconds, you must divide the distance by the speed the train is traveling. In this case you would have 1620/36 or 45 seconds.
To find the speed in KM/H, you could multiply the speed by 3,600, as there are 3,600 seconds in an hour, in order to find M/H. This would give you 129,600. After this you simply divide by 1,000 (1,000 meters in a kilometer) in order to get 129.6.
Hope this helps, and if you need further explanation, please feel free to ask.