问题如下：
A trader has purchased 200 shares of a non-dividend-paying firm on margin at a price of $50 per share. The leverage ratio is 2.5. Six months later, the trader sells these shares at $60 per share. Ignoring the interest paid on the borrowed amount and the transaction costs, what was the return to the trader during the six-month period?
选项：
A. 20 percent.
B. 33.33 percent.
C. 50 percent.
解释：
C is correct.
The return is 50 percent. If the position had been unleveraged, the return would be 20% = (60 - 50)/50. Because of leverage, the return is 50% = 2.5 × 20%.
Another way to look at this problem is that the equity contributed by the trader (the minimum margin requirement) is 40% = 100% ÷ 2.5. The trader contributed $20 = 40% of $50 per share. The gain is $10 per share, resulting in a return of 50% = 10/20.
给答案的第一种解题思路 老师根本就没有在基础班视频里面讲过…