Question

Trains leave Geelong for Melbourne every 40 minutes the first train leaves at 5:10am which departure time is closet to 12:55pm

Answer 1

5:10, 5:50, 6:30, 7:10, 7:50, 8:30, 9:10, 9:50, 10:30, 11:10
11:50, 12:30, 1:10

btween 12:30 and 1:10

12:30 is 25 mins before
1:10 is 15 mins after

Take your pick :)

Answer 2

Thank you

Answer 3

The LCM of 40 minutes and 60 minutes is 120 minutes or 2 hours.
So if the first train is at 5:10, there should definitely be a train at 7:10 and every (odd hour:10). So there will be one at 11:10. After that 11:50 AM then12:30 PM which is 25 mins before 12:55 PM. The next one is 1:10 PM which is 15 mins after 12:55 PM. So the closest is 1:10 PM.