Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m.By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?
解释:假设前年Price per share =x, 前年earning per share =y 那么去年的price per share 为(1+k%)x,去年的earning per share 为(1+m%)y 求 去年的price per share 与earning per share的比率 比前年的比率增加了多少。 [(1+k%)x]/[(1+m%)y ]/(x/y)再减1 =(1+k%)/(1+m%)再减1 =(k%-m%)/(100-m%) = [100(k-m)]/(100+m) %