826 - Math - Problem Solving

Question: An express train traveling at 72 km/hr speed crosses a goods train traveling at 45 km/hr speed in the opposite direction in half a minute. Alternatively, if the express train were to overtake the goods train, how long will it take to accomplish the task. Assume that the trains continue to travel at the same respective speeds as mentioned in case 1.

1. Cannot be determined
2. 30 seconds
3. 150 seconds
4. 130 seconds