A movie theater runs two movies continuously one for 40 minutes and the other 60 minutess Both begin at 300 pm when will again same time?

The earliest time that the two movies will again start at the same time is when the difference in their start times is a multiple of their least common multiple (LCM).

The LCM of 40 and 60 is 120 minutes, so the movies will again start at the same time 120 minutes after they both began.

That is, at 3:00 pm + 120 min = 5:00 pm.