Deepak only needs to use 2/3 of the recipe if he only wants to make 2/3 of the amount it produces.
12/3 = 4 ounces of butter per 6 cupcakes
6/3 = 2 ounces of sugar per 6 cupcakes
9/3 = 3 ounces of flour per 6 cupcakes
3/3 = 1 egg per 6 cupcakes
You then need to multiply all of those answers by 2 to get the answer for 2/3 as those are the answers for 1/3.
4x2 = 8 ounces of butter
2x2 = 4 ounces of sugar
3x2 = 6 ounces of flour
1x2 = 2 eggs