Cookie recipe uses 2 1/4 cup of flour per batch. want to use 13 1/2 cups of flour. needs 3 sticks of butter for every batch. how many sticks of butter needed.

To find out how many batches you need to get 13 1/2 cups of flour you divide 13.5/2.25 = 6.   so you need 6 batches to get 13 1/2 cups of flour.   each batch needs 3 sticks of butter so 6·3= 18.   so you will need 18 sticks of butter.   hope i !