You are the buyer for your university bookstore. One of the textbooks has a cost to you of $170 and you sell it to students for $280. Any copies of the book that you order and do not sell to students can be returned to the publisher for an average $80 credit. (Sometimes you can get full credit, but sometimes a new edition is published so you get no credit.) In one particular course, demand has averaged 540 books each semester, with a standard deviation of 54. Use Appendix A. a. What is your target service level? (Round your answer to 2 decimal places.) b. What is your target order quantity for the course? (Round your intermediate calculations to 2 decimal places. Round up your answer to the next whole number.)