ANSWER TO THE TIRE PROBLEM

THE ANSWER IS 9 TIRES. If you rotate 9 tires you can avoid buying 12 tires.

Miles

tire 1 300 300 300 300

tire 2 300 300 300 300

tire 3 300 300 300 300

tire 3 300 300 300 300

tire 4 300 300 300 300

tire 5 300 300 300 300

tire 6 300 300 300 300

tire 7 300 300 300 300

tire 8 300 300 300 300

tire 1	300						300	300	300
tire 2	300	300					300	300
tire 3	300	300	300						300
tire 3	300	300	300	300
tire 4		300	300	300	300
tire 5			300	300	300	300
tire 6				300	300	300			300
tire 7					300	300	300	300
tire 8						300	300	300	300