Jeremy is the oldest of four brothers. Each of the four boys gets an allowance for doing chores at home each week. The amount of
money each boy receives depends on his age. Jeremy is 13 years old, and he gets $12.75. His 11-year-old brother gets $11.25, and his 9-year-old brother gets $9.75. How much money does his 7-year-old brother earn?
