Mrs. Richard uses 115 1/2 cups of flour to make 2 3/4 dozen cakes. How many cups of flour does Mrs. Richard need to make a dozen cakes?

Mrs. Richard will need 42 cups of flour to bake 12 cakes or a dozen cakes.

Step-by-step explanation:

Number of cups of flour Mrs. Richard used to bake 2 3/4 doze cakes = 115 1/2

Number of cakes Mrs. Richard baked = 2 3/4 dozens

How many cups of flour does Mrs. Richard need to bake a dozen cakes?

Number of cakes Mrs. Richard baked = 2 3/4 dozens

Number of cakes Mrs. Richard baked = 2 3/4 * 12 (To find out the exact number)

Number of cakes Mrs. Richard baked = 11/4 * 12

Number of cakes Mrs. Richard baked = 11 * 3 = 33 (Dividing by four)

If Mrs. Richard needed 115 1/2 cups of flour for baking 33 cakes, how many cups she will need to bake 12?

Using the rule of three simple, we have this:

(115 1/2 * 12) / 33 = 1,386 / 33 = 42

Mrs. Richard will need 42 cups of flour to bake 12 cakes or a dozen cakes.