What equation(s) do I use to go about solving this problem and what numbers do I plug in where? I am lost.

{5.} 1|] Points You feel very strongly that the stock in McDonald's Corporation is about to fall from its present level of $55 per share. You call your broker and have him sell 5,055 shares short. This costs you $525 in commissions. {a} By law, what's the minimum amount of cash you have to have in your account before your broker will do this trade'? [2 Points] As anticipated, McDonald's stock drops to a low $45 per share. You call your broker and have him repurchase the 5.500 borrowed shares. This costs you $525 in commissions. {b} If during the time you sold this stock short, McDonald's stock paid a dividend of $5.55 per share. calculate your total rate of retum for this investment. Assume that the cash you originally had in your account was the minimum required by law. [5 Points]