The owner of a boutique desires to calculate the percentage of customers who purchase hats. If 40% of the store's customers purchase items, and of those customers, 15% purchase hats, then what is the percent of the store's customers purchase hats?

We are asked to solve for the percent that customers in the store will buy hats.

We let "x" equal to the number of people who went to the store.

When 40% of this buy from the store or purchase items, we have:

40% x X = 0.4X

When 15% of the 40% bought hats, we have:

15% x 0.4X = 0.06X - > 6% of X

Therefore, the answer is 6% of the total population who come to the store will buy hats.