Answer :
she will need to buy at least three hundred and twenty four cards (324) cards.
The lowest common multiple of 12 and 27 is 108.
12 x 9 = 108 and
27 x 4 = 108 .
So she has to buy 9 packs of cards ... 108 of them ... and 4 packs of envelopes.
12 x 9 = 108 and
27 x 4 = 108 .
So she has to buy 9 packs of cards ... 108 of them ... and 4 packs of envelopes.