Question

Bill and Jill both exercise on Monday, January 1. Bill exercises every 5th day, and Jill exercises every 4th day. What is the next date on which Bill and Jill both exercise?

Answer 1

• January 20

Explanation:

5 and 4 mutually prime numbers, therefore we need to find their LCM.

• LCM(5,4) = 5*4 = 20

Next time they will both exercise on the 20th days, which is January 20