又一道不会的prep!!!

lllmmm

With a record number of new companies starting up in Derderia and with previously established companies adding many jobs, a record number of new jobs were created last year in the Derderian economy.  This year, previously established companies will not be adding as many new jobs overall as such companies added last year.  Therefore, unless a record number of companies start up this year, Derderia will not break its record for new jobs created.

Which of the following is an assumption on which the argument relies?

(A) Each year, new companies starting up create more new jobs overall than do previously established companies.
(B) Companies established last year will not add a greater number of jobs overall this year than they did last year.
(C) This year, the new companies starting up will not provide substantially more jobs per company than did new companies last year.
(D) This year, the overall number of jobs created by previously established companies will be less than the overall number of jobs lost at those companies.
(E) The number of jobs created in the Derderian economy last year was substantially larger than the number of jobs lost last year.

sdcar2010

B) is not necessary. If you negate B), meaning established firms hire more people than last year, that factor alone cannot guarantee an increase in the total this year because maybe the startups hire zero or only 1 person this year.  So the conclusion may still hold.

huyuhan7

B为什么不对。

littlexian

Answer C.

NN sdcar2010 and NN 大马oz already have nice and clear explaination.

大马oz

sdcar2010真是牛人啊，看到他解释了很多语法逻辑什么的，很专业，应该是教GMAT的大牛吧。呵呵。仰慕一下。

我也觉得此题选C。

题目说D城新公司创立的数目去年创了新高，加上原来已有的公司也放了很多位置出来，因此去年新工作的数量创了新高。今年，原来已有的公司不会再招这么多人了。因此，除非今年新公司创立的数目能再创新高，否则D城新工作的数量不会超过去年再创纪录。

可是如果出现这样的情况呢？比如，今年虽然只开了一家新公司H，因此新公司的数目远远少于去年的1000家。但是H公司一上来，就要招100万员工，那么恐怕整座D城都是它的手下了。这样D城新工作的数量一定又创记录了。

选项C恰恰是对这种假设的否定。

祝大家杀鸡愉快。同求祝福。

sdcar2010

Necessary assumption. Use negation.

New Job Created = Jobs created by "previously established companies" + Jobs created by "starup companies"

If you negate C, you have: This year, the new companies starting up will provide substantially more jobs per company than did new companies last year. If this is true, although no new jobs will be created by "old companies," it is possible that jobs created by "new companies" might exceed the total number of jobs created last yeart. Then the argument falls apart. So C is the necessary assumption.

In terms of math:
A = 100 (old companies) + 200 (new companies)
B = 99 (old companies) + x (new companies)

If the conclusion says that B<A, then x has to be less than 200 (last year's new job number).

C) unless a record number of companies start up this year, Derderia will not break its record for new jobs created:

Not A unless B: If A, then B; If not B, then not A.

The total new jobs created by new companies = number of new companies * average number of new jobs created in each new company. Even if the number of new companies drops or remains the same as last year, if the average number of new jobs per new company reaches a new height, the total number of new jobs might still be a record.  C simply prevents that from happening.

Rainbeauty

凭我的感觉选A
用取非选的
选项分析：B---有点重复题目了 C---并不符合题意  D和E---无关 似乎并木有提到job loss