If you construct a bond portfolio with five $6\%$ coupon $($semiannual payment$),$ duration of $2\mathrm{.}79$ years, $3-$year maturity bond sells at par $($$$1,000)$ and six $1-$year zero coupon bond sells for $$950.$

$($a$)$ Calculate the portfolio duration.

$($b$)$ Calculate the yield for the portfolio.