How many copies should the bookstore stock to achieve highest expected value?

The University of Dallas bookstore stocks textbooks in preparation for sales each semester. It normally relies on departmen­tal forecasts and preregistration records to determine how many copies of a text are needed. Preregistration shows 90 operations man­agement students enrolled but bookstore manager Curtis Ketterman has second thoughts based on his intuition and some historical evi­dence. Curtis believes that the distribution of sales may range from 70 to 90 units according to the following probability model:Demand7075808590Probability.15.3030.20.05This textbook costs the bookstore $82 and sells for $112. Any unsold copies can be returned to the publisher less a restocking fee and shipping for a net refund of $36.a) Construct the table of conditional profits.b) How many copies should the bookstore stock to achieve highest expected value?