Question

The teachers’ editions of a statistics textbook sell for $150 each, and students’ editions of the book sell for $50 each. Which function can be used to find the average cost per book if two teachers’ editions and x students’ editions are purchased?

Answer 1

Total cost = 2(150) + x(50) = 300 + 50x. Number of books = 2 + x.

Average cost per book A(x) = (300 + 50x)/(2 + x) = 50(x + 6)/(x + 2), for x ≥ 0.