An investor wants to find the duration of$$ a$($n$)25-$year, $5\%$ semiannual$$ pay, noncallable bond$$ that's currently priced in the market at $$$$411\mathrm{.}02,$ to yield $13\%.$ Using a $150$ basis point change in$$ yield, find the effective duration of this bond $($Hint$$: use Equation$11\mathrm{.}11).$