Assume that $[]$ E RM $=15\%($expected return of the market$),$ Rf $=5\%($risk$-$free rate of return$)$ and

$\backslash$sigma M $=20\%($standard deviation of the returns of market$).$ Common stock of the Rapid Roller

Corporation has $[]$ E Rk $=25\%$ and $2\backslash$sigma k $=52\%.$

a$)(2$ marks$)$ What is the systematic risk of the common stock?

b$)(3$ marks$)$ What is its unsystematic risk?