Bill Campbell invested $4,000 and borrowed $4,000 to purchase shares in Walmart. At the time of investment, Walmart stock was selling for $62 a share.

a. If Bill paid a $30 commission, how many shares could he buy if he used only his own money and did not use margin?

b. If Bill paid a $50 commission, how many shares could he buy if he used his $4,000 and

c. Assuming Bill did use margin, paid a $90 total commission to sell his Walmart stock, and sold his stock

for $75 a share, how much profit did he make on his Walmart investment?