Question

A movie theater runs its films continuously. One movie runs for 85 minutes and a second runs for 110 minutes. The theater has a 5-minute intermission after each​ movie, at which point the movie is shown again. If both movies start at​ noon, when will the two movies start again at the same​ time?

Answer 1

10:30PM on the next day

Explanation:

First movie = 85mins

intermission = 5mins

Total time = 90mins which is 1:30PM

so the first movie will start again at 1:30PM, which is at the interval of 90minutes and it will run continuously.

Similarly the second movie is 110 minutes long + 5mins intermission which is 115minutes

Time = 1:55PM

so the second movie starts again at 1:55PM and runs continuously at an interval of 115minutes.

We are interested to find when both the movie will start again at the same time, this will be least common multiple of 90 and 115.

LCM of 90,115 = 2070

Therefore after 2070minutes movie will start again at the same time.

2070mins = 34hours and 30 minutes

adding this with noon

10:30PM on the next day.