Answer:
72 cupcakes
Step-by-step explanation:
Morgan can make 4 cupcakes with one cup of flour. She has 18 cups of flour and suppose she can make x cupcakes, then
1 cup of flour - 4 cupcakes
18 cups of flour - x cupcakes
Write a proportion:

Cross multiply:

D. 5x = 45 because you are trying to find x, the number of tickets that must be sold to earn $45.