求助

Ice_cream_nn

请问gmatprep破解版中的第147题怎么算？

147.
                    14800-!-item-!-187;#058&010134

Each employee on a certain task force is either a manager or a director.  What percent of the employees on the task force are directors?

 

(1) The average (arithmetic mean) salary of the managers on the task force is $5,000 less than the average salary of all employees on the task force.

 

(2) The average (arithmetic mean) salary of the directors on the task force is $15,000 greater than the average salary of all employees on the task force.

rachelq5

我是设的manager,director平均工资分别x,y元，人数分别m,n人。（1）（2）各列两个等式，单独看都没法得出n/(m+n),两个放一块经过化简也得不出。