Beth had made 12 cupcakes. This is 30% of the cupcakes she must make. How many cupcakes must she make?

What we know:

12 cupcakes already made

12 is 30% of total cupcakes (c) needed

Total cupcakes c are 100%

What we need to find:

Total cup cakes c

Set up propportion:

12/30=c/100

30c = (12) (100)

30c=1200

30/30c=1200/30

c=40

She needs to make a total of 40 cupcakes.