Answer:
Use 1 cup sugar to make 2 dozen (24) cookies.
Explanation:
Recall that 1 dozen = 12 pieces
Write and solve an equation of ratios: # of cookies on one side and # of cups of sugar on the other side:
18 cookies (3/4) cup sugar
--------------------- = ------------------------
24 cookies x
Cross-multiplying results in:
18x = 18, so that x must be 1.
Use 1 cup sugar to make 2 dozen (24) cookies.