Assuming $320$ PSA for a given mortgage pool, what is the monthly prepayment rate $($SMM$)$ for month $340?$

$1\mathrm{.}43\%$

$0\mathrm{.}51\%$

$1\mathrm{.}76\%$

$0\mathrm{.}71\%$

Consider a convertible bond trading at $$1,000$ with a coupon rate of $9\mathrm{.}5\%,10$ years to maturity, and a par value of $$1,000.$ If comparable nonconvertible bonds yield $18\mathrm{.}7\%,$ what is the premium over straight value?

$51\mathrm{.}19\%$

$16\mathrm{.}41\%$

$69\mathrm{.}39\%$

$38\mathrm{.}98\%$