Question

in a cookie jar,1/5 of the cookies are chocolate chip and 1/2 of the rest are peanut butter.What fraction of all the cookies is peanut butter?

Answer 1

If 1/5 are chocolate chip, then 4/5 are not chocolate chip because 1 - 1/5 = 4/5.

Half of 4/5 are peanut butter. Half of 4/5 is 2/5, so 2/5 of the cookies are peanut butter.