Brian Campbell invested $4,000 and borrowed $4,000 to purchase shares in a large retailing company. At the time of investment, the stock was selling for $45 a share.
a. If Brian paid $70 commission, how many shares could he buy if he used only his own money and did not use margin?
b. If Brian paid $100 commission, how many shares could he buy if he used his $4,000 and borrowed $4,000 on margin to buy the retailing company's stock?
c. Assuming that Brian did use margin, paid $250 commission to buy and sell his stock, and sold his stock for $53, how much profit did he make on his retailing company's investment?