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?

- 400
- 500
- 600

- I only (check answer)
- II only (check answer)
- I and II only (check answer)
- II and III only (check answer)
- 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.