$($c$)$ Let $r_1$ and $r_2$ be the annual returns both normally distributed with means $0\mathrm{.}4$ and $0\mathrm{.}3$ and

standard deviations $0\mathrm{.}2$ and $0\mathrm{.}35,$ respectively. The correlation between $r_1$ and $r_2$ is $-0\mathrm{.}6.$

An investment has a value $R=60(1+r_1)-10(1+r_2).$ Calculate the downside semi$-$

variance of $R.$