Question

a movie theater has two screens and shows it’s movie continuously. a 30 minute documentary is shown on one screen. a 90 minute feature is shown on the other screen. if both movies begin at noon, how many minutes will pass before both movies begin again at the same time?

Answer 1

Answer is: 30x = 90y

Answer 2

To answer this item, we let x be the number of times that the 30-minute documentary is shown and y be the number of times that the 90-minute documentary is shown. By the given scenario in the item, we have,

30x = 90y

The least common multiple (LCM) of the numerical coefficients of the equation is equal to 90. Thus, 90 minutes will pass and the documentaries will start again.