Starting at the same time, Bill rings a bell every $36$ seconds, and Wendy blows a whistle every $90$ seconds, and Sam blows a horn every $385$ seconds. How many minutes will it be before both Bill and Wendy and Sam simultaneously make a sound?
Using prime factoriazation
36 = 2 x 2 x 3 x 3
90 = 2 x 3 x 3 x 5
385 = 5 x 7 x 11
2 x 2 x 3 x 3 x 5 x 7 x 11 = 13860 seconds = 231 minutes