John Smith opens a brokerage account and purchases 400 shares of Folda Valve Inc. at $35 per share on margin. Initial margin requirement is 50% and his broker charges 4% interest rate over his one-year investment period. Maintenance margin is 30%. a. What is the margin in his account at the time of purchase? b. If the price increases to $40 per share by the end of the year, what is the return on John's investment? c. If price goes down to $30 per share what is the return on his investment? d. What is the price at which he receives a margin call