My cupcake recipe makes 12 cupcakes and requires 2 sticks of butter. I can only buy whole sticks of butter. How many whole sticks of butter must I buy to make 200 cupcakes?
So if 2 sticks of butter make 12 cupcakes... and we set the number of cupcakes as c and the number of sticks of butter as b, we get
12c = 2b
dividing each side by 2 we get
6c = 1b
Since we need 200 cupcakes, we divide 200 by 6 and get 33.3, which we round up because we need 200 cupcakes or more
so we multiply the equation 6c = 1b by 34, and get 34 sticks of butter