Please step by step answer on this and on how to do it using Excel and show all formulas, answer the questions almost as if it is for dummies thank you. Please show where the numbers are coming from thank you.

13. An analysis of the product line items in the retail stores of the Save-More Drug chain shows that 20 percent of the items stocked account for 65 percent of the dollar sales. A typical store carries 5,000 items. The items accounting for the top 75 percent of the sales are replenished from warehouse stocks. The remainder is shipped directly to stores from manufacturers or jobbers. How many items are represented in the top 75 percent of sales