An investor wants to find the duration of $a(n)15-y$ ear, $5\%$ semiannual pay, noncallable bond that's currently priced in the market at $3518\mathrm{.}23,$ to yield $12\%.$ Using a $250$ basis point change in yield, find the effective duration of this bond $($Hint use Equation $11\mathrm{.}11).$

The new price of the bond if the market interest rate decreases by $250$ basis points $($or $2\mathrm{.}5\%)$ is: $($Round to the nearest cent.$)$