Question

Nikki has rowing lessons every four days and tennis every 7 days. If she had both lessons on the last day of the previous month, when will she have both lessons on the same day of the current month?

Answer 1

we know that

Nikki has rowing lessons every four days

so

4 8 12 16 20 24 28

and

tennis every 7 days

7 14 21 28

therefore

She will have both lessons again the day 28 of the current month