The campus bookstore knows from the past several semesters that a certain elementary statistics book has a demand that is approximated by a normal distribution with a mean of 250 and a standard deviation of 40. They buy these books for $105 each and sell them to unsuspecting undergraduates at $222 each. All demand for this book is realized by the middle of the semester, at which point the bookstore bundles them up and sells them to a vendor in another country for $40 each. What is the marginal profit for a single elementary statistics book