To find the next week in which all three coincide, look for the lowest common multiple of the numbers 2,3, and 6. Two has multiples of (2,4,6,8,10,12), three has (3,6,9,12,15,18), and 6 has (6,12,18,24). The lowest number that is common to all three values is 6, so Clea will attend all three in the same week 6 weeks from now.
