Calculate the annual interest and effective interest rates of purchasing 50 DoggyDigs (DD) bonds maturing...

7. Calculate the annual interest and effective interest rates of purchasing 50 DoggyDigs (DD) bonds maturing in 2010.
The annual interest is $12,634.50. The bonds have an effective interest rate of approximately 3.5%.
The annual interest is $3,474.50. The bonds have an effective interest rate of approximately 1.30%.
The annual interest is $6,949.75. The bonds have an effective interest rate of approximately 9.7%.
The annual interest is $8,548.00. The bonds have an effective interest rate of approximately 5.8%.