You buy a $20-$year bond with a coupon rate of $9\mathrm{.}2\%$ that has a yield to maturity of $10\mathrm{.}2\%.($Assume a face value of $$1,000$ and

semiannual coupon payments.$)$ Six months later, the yield to maturity is $11\mathrm{.}2\%.$ What is your return over the $6$ months?

Note: Do not round intermediate calculations. Enter your answer as a percent rounded to $2$ decimal places. Negative amount

should be indicated by a minus sign.

Answer is complete but not entirely correct.

Please explain the correct answer :)