Please help me solve (I was able to get question 2 but I can't figure out 3 or 4)

When answering below Questions 2 - 4, Consider the following conditions: XYZ company is planning to set up an additional warehouse in its distribution network. Analysis of itemsales data for other warehouses shows that 20 percent of the items represent 75 percent of the sales volume. The company also has an inventory policy that varies with the items in the warehouse. That is, the first 20 percent of the items are the A items and are to be stocked with an inventory turnover ratio of 8.5. The next 30 percent of items, or B items, are to have a turnover ratio of 8 . The remaining C items are to have a turnover ratio of 7.5. There are to be 20 products at the warehouse with sales on the warehouse forecasted to be $5 million annually. Question 2. What is the value for the constant A in this problem? Question 3. What is the percentage of items which are represented in the top 85 percent of sales? Question 4. What is the inventory value generated by items in C class