# Average Age Puzzle (VIDEO!)

Ten students sit in a circle. Their ages happen to have the astounding property that the age of any one student equals the average of the ages of her two immediate neighbours. Betty is 15. How old is Jake?

Ten students sit in a circle. Their ages happen to have the astounding property that the age of any one student equals the average of the ages of her two immediate neighbours. Betty is 15. How old is Jake?