【求助】prep一道关于比例的数学题

RayeRach

each employee on a certain task force is either a manager or a director.What percent of employees on the task force are directors?
(1)the average 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 salary of the direcors on the task force is 15,000 greater than the average salary of all emplyees on the task force

大家能详细点给解答下吗？谢谢大伙儿咯

Goco

因为manager比Ave一共少的金额是和director比ave一共多的金额相等的，
所以，M平均每人少的金额*M的人数 = D 平均每人少的金额* D的人数，这样的话，M/D=15000/5000=3
D/Total=1/4

yzg1236

设 p1 是manager 的平均工资，
p2  director 的平均工资
p  总的平均工资
M 是manager 的人数
D 是director 的人数

p1 = p - 5000
p2 = p + 15000

(p1*M + p2*D) = p * (M + D)
(p - 5000)*M + (p + 15000)*D = P(M + D)

p*M + p*D - 5000*M + 15000*D = p*M + p*D

15000*D = 5000*M

RayeRach

谢谢大家！节日快乐！