$6.$ Two years ago, you bought $300$ shares of Kayleigh Milk Co$.$ for $$30$ a share with a margin of $60$ per$-$cent. Currently, the Kayleigh stock is selling for $$45$ a share. Assuming no dividends and ignoring commissions, $($a$)$ compute the annualized rate of return on this investment if you had paid cash and $($b$)$ your rate of return with the margin purchas