问题
单项选择题
One year ago, an investor made five separate investments with the invested amounts and returns shown below. What is the arithmetic and geometric mean return on all of the investor's investments（）
A．15.79%
B．2.3%
C．10.79%
答案
参考答案：C
解析：
Arithmetic Mean: 12 + 14 +9 + 13 +7 =55; 55/5 = 11 ; Geometric Mean:
