neverminding for a second how many bags of chips or bars are in either box, we know the price for the box of chips is $13.80, so we can say that prices are
1 box............13.80(1)
2 box............13.80(2)
3 box............13.80(3)
4 box............13.80(4)
x box............13.80(x)
or namely 13.80x.
likewise weca san say about the candy boxes that prices are
1 box............6.60(1)
2 box............6.60(2)
3 box............6.60(3)
4 box............6.60(4)
y box............6.60(y)
or namely 6.60y
we know Maria only has $100, so whatever "x" and "y" are, must fit within the constraint of those 100 bucks, so 13.80x + 6.60y must be either less or equals to 100 bucks, but not more, since it's all Maria has, thus
13.80x + 6.60y ⩽ 100
