[問題]GMATPrep PP1-28

[shine822]

我要問的問題是最新 GMATPOWERPREP程式 裡面的問題
但我因為沒啥人有OG11th 所以暫時無法對照題號甚至不清楚是否有重複
請見諒!!

我已想盡辦法 新發明比較好辨認的題號了
當然版主大大若有更好的同一格式
請隨意修改標題 感激不盡

Practice1
Q28. DS:
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 the full-time employees to the part-time employees greater for Division X than for company Z?

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

(2)more than 1/2 full-time employees of company Z are Division X and more than 1/2 part-time employees of company Z are Division Y

Ans. D


我只能看出第二個條件對 第一個條件看不出來
為了讓大家都清楚
我把我懂的部份也列出來:

F表示full-time employee P=part-time employee
(Z)=company Z, (X)=Division X, (Y)=Division Y

題問: F(X)/P(X) < F(Z)/P(Z) ?
已知: F(Z)=F(X)+F(Y), P(Z)=P(X)+P(Y)

(2): F(X)>1/2F(Z), P(X)<1/2P(Z)
=> (>1/2)F(Z)/(<1/2)P(Z) > F(Z)/P(Z)
答案是相反的 所以充分 (O)

(1): F(Y)/P(Y) < F(Z)/P(Z)

怎麼想都想不通 是如何能推導出來題目的
請幫忙 感激不盡!!!!!

[zazer.lin]

Q28. DS:
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 the full-time employees to the part-time employees greater for Division X than for company Z?

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

F表示full-time employee P=part-time employee
(Z)=company Z, (X)=Division X, (Y)=Division Y

題問: F(X)/P(X) < F(Z)/P(Z) ?
已知: F(Z)=F(X)+F(Y), P(Z)=P(X)+P(Y)

(1): F(Y)/P(Y) < F(Z)/P(Z)

為了方便起見, 小弟繼續延用您的符號來解釋 statement(1)
(1): F(Y)/P(Y) < F(Z)/P(Z)
==> F(Y)P(Z) < F(Z)P(Y) .........................(上式交叉相乘)
==> F(Y)[P(X)+P(Y)] < [F(X)+F(Y)]P(Y) ......(還原P(Z) 和 F(Z))
==> F(Y)P(X) < F(X)P(Y) ..........................(因為不等式兩邊都有F(Y)P(Y), 故可以相消)
==> F(X)P(X) + F(Y)P(X) < F(X)P(Y) + F(X)P(X) .....(不等是兩邊同加上F(X)P(X))
==> P(X)[F(X)+F(Y)] < F(X)[P(X)+P(Y)] .......(上面的不等式兩邊各自提公因數)
==> P(X)F(Z) < F(X)P(Z)
==> F(Z)/P(Z) < F(X)/P(X)
故答案應該沒錯, 應該為(D)

老實說, 這一題要是在機考的時候出現, 我跟您一樣也會選(B).
所以說做題目還是要靜下心來, 還有, 不能懶惰, 我一開始會選(B)的原因就是因為我沒動筆去算

[shine822]

為了方便起見, 小弟繼續延用您的符號來解釋 statement(1)
(1): F(Y)/P(Y) < F(Z)/P(Z)
==> F(Y)P(Z) < F(Z)P(Y) .........................(上式交叉相乘)
==> F(Y)[P(X)+P(Y)] < [F(X)+F(Y)]P(Y) ......(還原P(Z) 和 F(Z))
==> F(Y)P(X) < F(X)P(Y) ..........................(因為不等式兩邊都有F(Y)P(Y), 故可以相消)
==> F(X)P(X) + F(Y)P(X) < F(X)P(Y) + F(X)P(X) .....(不等是兩邊同加上F(X)P(X))
==> P(X)[F(X)+F(Y)] < F(X)[P(X)+P(Y)] .......(上面的不等式兩邊各自提公因數)
==> P(X)F(Z) < F(X)P(Z)
==> F(Z)/P(Z) < F(X)/P(X)
故答案應該沒錯, 應該為(D)

老實說, 這一題要是在機考的時候出現, 我跟您一樣也會選(B).
所以說做題目還是要靜下心來, 還有, 不能懶惰, 我一開始會選(B)的原因就是因為我沒動筆去算

太強了!!
這不僅僅是不懶惰吧~ 同加F(X)P(X)這一招 還真是帥氣

而且你願意延用我那難打的符號 辛苦你了
感激不盡!!