OK, jc: I think I know what you did wrong. Look below:
1-year CD that pays 3% compounded semi-annually. $22,811.55 X (1.015)^2=$23,501.03
2-year CD that pays 4% ............................................. $21,711.32 X (1.02)^4 =same amount
3-year CD that pays 5%.............................................. $20,264.86 X (1.025)6 =same amount
4-year CD that pays 6%.............................................. $18,551.93 X (1.03)^8 =same amount
5-year CD that pays 7%.............................................. $16,660.32 X (1.035)^10=same amount