Suppose that Intel is currently selling at $40 per share. You buy 250 shares by using $7,500 of your own money and borrowing the remainder of the purchase price from your broker. The rate on the margin loan is 4% per annum. What is the rate of return on your margined position if Intel is selling after one year at $34?

-18.7%

+20%

-20%

-21.3% <----- This is the correct answer, what is the work?