Assume an initial margin requirement of 50 percent and a maintenance margin of 30  percent. If you buy 100 shares of stock on margin at $60 per share and the price of the stock subsequently drops to $50.
 
i).  What is the actual margin at $50?
ii)  The price now rises to $55. Is the account restricted?
iii)  If the price drops to $49, is there a margin call?
iv)  Assume that the price declines to $45. What is the amount of margin call? At $35?