Question

10. Mr. Sanchez goes to the movies every 18 days. His brother goes to the

movies every 30 days. If they were at the movies together this evening,
how many more days will it be before they are at the movies together
again? 5.NF.2

Answer 1

90 days.

For this question you just need to find the least common multiple of 18 and 30. That can be found by first finding the prime factorization of each number. 18 = 2 * 3 * 3 and 30 = 2 * 3 * 5. Then you multiply the 2 * 3 * 3 * 5, you ignore the 3 from 30 because 18 has more 3s. The answer is 90.