4. In anticipation of the immense college expenses, a couple have started an annual investment program on their child's eighth birthday that will last until the eighteenth birthday.

The couple estimate that they will be able to invest the following amounts at the beginning of each year:

Year 1 Amount ($) 2000 2 3 2000 2500 4

2500 5

3000 6 7 8 9 3500 3500 4000 4000 10 5000 To avoid unpleasant surprises, they want to invest the money safely in the following options:

Insured savings with 7.5% annual yield, six-year government bonds that yield 7.9%

and have a current market price equal to 98% of face value, and nine-year municipal bonds yielding 8.5% and having a current market price of 1.02 of face value. How should the couple invest the money?