A person is interested in constructing a portfolio. Two stocks are being considered. Let x$=$ percent return for an investment in stock $1,$ y$=$ and percent return for an investment in stock $2.$ The expected return and variance for stock $1$ are E$($x$)=9\mathrm{.}84\%$ and Var$($x$)=36.$ The expected return and variance for stock $2$ are E$($y$)=4\mathrm{.}50\%$ and Var$($y$)=4.$ The covariance between the returns is $-3.$

A$.$ What is the expected percent return and standard deviation for a person who constructs a portfolio by investing in each stock $($to $3$ decimals$)?$

B$.$What is the expected percent return and standard deviation for a person who constructs a portfolio by investing $70\%$ in stock $1$ and $30\%$ in stock $2($to $3$ decimals$)?$