Yankee Athletic Club has preferred stock with a par value of $$60$ and an annual $6\%$ cumulative dividend. Given the following prices for the preferred stock, what is each investor seeking for his or her return?

a$.$ Alex is willing to pay $$40.$

b$.$ Derek is willing to pay $$25.$

c$.$ Marcia is willing to pay $$20.$

d$.$ Johnny is willing to pay $$10.$

a$.$ If Alex is willing to pay $$40$ for the preferred stock, what rate of return is he seeking?

$\%($Round to two decimal places$)$

b$.$ If Derek is willing to pay $$25$ for the preferred stock, what rate of return is he seeking?

$\%($Round to two decimal places$)$

c$.$ If Marcia is willing to pay $$20$ for the preferred stock, what rate of return is she seeking?

$\%($Round to two decimal places