Astore is selling 61/2 ounce bags of flour. the recipe for cupcakes calls for 1/3 ounce of flour. how many whole cupcakes can u make using the whole bag of flour.

I must assume that you meant "6  1/2" and not "61 / 2."

If each cupcase requires 1/3 ounce of flour, then the total whole cupcakes that can be made using the entire 6 1/2 oz. bag is

6 1/2 oz                     13 oz      1 cupcake
= * = 39 cupcakes (answer)
 1/3 oz / cupcake         2             (1/3 oz)