请教一道DS的题 关于不等式

问答者你好吗

Each employee of Company Z is an employee of either division X or division Y, but not both. If each division has some part time employees, is the ratio of the number of full-time employees to the number of part-time employees greater for division X than for Company Z?

(1) the ratio of the number of full time employees to the number of part-time employees is less for division Y than for Company Z

(2) More than half of the full-time employees of Company Z are employees of Division X, and more than half of the part-time employees of Company Z are employees of Division Y


答案是D 两个分别都可以


有谁可以解释一下吗？特别是为什么第二个是可以得？谢谢!

行素

hansoncheng 发表于 2019-6-24 14:35
设 X部门里的 part-time p1 ，full-time f1
    Y部门里的 p2 f2

确实不太好表达，字母一大推好容易抄错，是不是赋值法会容易点？

hansoncheng

设 X部门里的 part-time p1 ，full-time f1
    Y部门里的 p2 f2

问的是
f1/p1 > (f1+f2)/(p1+p2) 吗
化简得 f1p2 > f2p1

条件1：f2/p2 > (f1+f2)/(p1+p2)  化简得 f1p2 > f2p1  充分
条件2：f1 > f2 , p2 > p1 两式相乘得 f1p2 > f2p1 充分


我上来也懵了 把整个公司得情况也用未知数表达出来 之后就越算越乱

一抹斜阳

顶楼主！