pp数学一道

jedylxl

求指点

tkrayla

1) 只知道manager的平均工资比全部雇员平均工资少5000，但是不知道director工资和雇员工资的关系 所以无效
2) 同理
1+2 设平均工资是M 有等式
M=[(M-5000)N(manager)+(M+15000)N(director)]/N(manager)+N(director)

jedylxl

明白了，THANK YOU

jellylulu

Let the number of directors equals to N_d and the number of managers equals to N_m, the average salary of the total population equals to x, we can have the following:

[N_d(15,000+x)+N_m(x-5,000)]/[N_d+N_m]=x

==>15,000N_d-5,000N_m=N_d+N_m

==>Thus, we can solve for the percentage of directors through this equation.