Nick has tennis practice every sixth day. Mark has tennis practice every 4th day. On July 31st they both had tennis practice. When will be the next time that they both have practice on the same day?

Answer 1

On July 31st they both had practice, so let's call that day 0.

Nick has practice every sixth day, so he'll have practice on day 6, 12, 18, 24, 30...

Mark has practice every fourth day, so he'll have practice on day 4, 8, 12, 16, 20...

What this question really wants us to do though, is find the least common multiple of 4 and 6.

From the list above, Mark has practice on day 4 but Nick doesn't. Nick has practice on day 8 but Mark doesn't. Mark has practice on day 8 but Nick doesn't. But they both have practice on day 12. (And 12 is the least common multiple of 4 and 6.)

So they'll both have practice on the same day 12 days from July 31st, or on August 12th.