The annual interest rate earned by an investment increased by 10 percent from last year to this year. If the annual interest rate earned by the investment this year was 1 percent, what was the annual interest rate last year?
A. 1% B. 1.1% C. 9.1% D. 10% E. 10.8%
参考答案C 是不是题目错了啊?我怎么觉得答案应该是0.91%呢?取近似值应该是A了. 设要求值为X (1+10%)X=1% ==>X=0.0091 大家快帮我看一下吧. | 
