Question

Jodi plans to make 5 dozen cupcakes. The recipe she uses is for 2 dozen cupcakes and calls for 1 1/2 cups of flour. How many cups of flour will Jodi need to make 5 dozen cupcakes?

Answer 1

2 dozens= 24 cupcakes.
5 dozens= 60cupcakes.
1.5/24= 0.0625 cups of flour/ cupcake.
0.0625 x 60= 3.75 cups of flour. 
                   = 3 3/4 cups of flour.

Answer 2

Either ratio or proportion or recognize that

2 times 2.5=5, so 1 and 1/2 times 2.5=amount needed
assuming you don't know that
ratio and proportion
pancakes/flour=2/1.5

2/1.5=5/x
times both sides by 1.5x
2x=7.5
divide both sides by 2
x=3.75 cups