At a bake sale, muffins are priced at 1.50 dollars each, and cookies are priced at 1 dollar for two. If 11 muffins are sold, and the total money earned is 29.50 dollars, how many cookies were sold?

Build an equation. Use m for muffins and c for cookies. The money earned for muffins is equal to the number of muffins times 1.50 dollars: 1.5m
The money earned for cookies is equal to the number of cookies divided by two times 1 dollar: \(\frac{c}{2}\)
The total money earned is the sum: t = 1.5m + \(\frac{c}{2}\)
Set the total equal to 29.50 dollars and plug in the number of muffins to solve for c:
29.5 = 1.5(11) + \(\frac{c}{2}\)
13 = \(\frac{c}{2}\)
c = 26