For his graduate seminar in psychology, Professor Ross bought several copies of Entrepreneurial Genius at $18 per copy and several copies of Empowerment at $29 per copy. In total he paid $289. How many copies of each book did he purchase?
Answer: The cost can be written as 18x + 29y where x and y denote the number of copies of each book. Since the total cost is $289, we write 18x + 29y = 289. Solving for y in terms of x yields y = (289 – 18x)/29. When we substitute x= 8, we obtain y = 5, so he purchased 8 copies of Entrepreneurial Genius and 5 copies of Empowerment.
