What is the answer? Please show the step by step.

You believe the stock in Freeze Frame Co. is going to fall, so you short 600 shares at a price of $72. The initial margin is 50 percent. Construct the equity balance sheet for the original trade. Now construct equity balance sheets for a stock price of $63 and a stock price of $77. What is your margin at each of these stock prices? What is your holding period return if you cover your short position at each of these prices in five months