There are 15 classrooms in Sunny Skies High School, numbered 1 through 15. Between classrooms 1 through 10, there are 250 math textbooks. Between classrooms 6 through 15 there are 300 math textbooks. Which of the following could be the total number of math textbooks in classrooms 1 through 15?

1. 400
2. 500
3. 600

1. I only (check answer)
2. II only (check answer)
3. I and II only (check answer)
4. II and III only (check answer)
5. I, II, and III (check answer)

Solutions, hints, and questions are welcomed. A full solution will be posted on October 26th. If you would like to learn how to enter math formulas into this blog, visit the WordPress LaTeX tutorial page.