In August, Walton Bookstore must decide how many of next year’s nature calendars should be ordered. Each calendar costs the bookstore $2 and is sold for $4.50. After January 1, any unsold calendars are returned to the publisher for a refund of 75¢ per calendar.

Walton believes that the number of calendars sold by January 1 follows the probability distribution shown in Table 1. Walton wants to maximize the expected net profit from calendar sales. How many calendars should the bookstore order in August?