James McCulloch purchased a $30-$year U$.$S$.$ Treasury bond four years ago for $$1,000.$ The bond paid $2\mathrm{.}1$ percent annual interest. Four years later he sold the bond for $$1,040.$

What is the annual interest amount for the bond?

What is the total interest Mr$.$ McCulloch earned during the four$-$year period?

What is the total return for Mr$.$ McCulloch's bond investment?