Answer :
you need to do this LCM(least common multiples)
6,12,18,24,30,36
9,18,27,36,45,54
18 is your answer.
6,12,18,24,30,36
9,18,27,36,45,54
18 is your answer.
The minimum she can buy for the pack of 6 is 3 and the minimum for the pack of 9 is 2.