Q30:
Printwell’s Ink Jet Division manufactures ink-jet printers and the

ink cartridges they use. Sales of its ink-jet printers have

increased. Monthly revenues from those sales, however, have not

increased, because competition has forced Printwell to cut the

prices of its printers. Unfortunately, Printwell has been unable

to bring down the cost of manufacturing a printer. Thus, despite

the increase in printer sales, the Ink Jet Division must be

providing the company with much smaller than it used to.

Which of the following, if true, most seriously weakens the

argument?

A. Ink-jet printers in regular use frequently need new ink

cartridges, and Printwell’s printers only accept Printwell’s ink

cartridges.
B. Unlike some competing companies, Printwell sells all of its

printers through retailers, and these retailers’ costs account for

a sizable proportion of the printers’ ultimate retail price.
C. Some printer manufacturers have been forced to reduce the sale

price of their ink-jet printers even more than Printwell has.
D. In the past year, no competing manufacturer of ink-jet printers

has had as great an increase in unit sales of printers as Printwell

has.
E. In the past year, sales of Printwell’s ink-jet printers have

increased more than sales of any other type of printer made by

Printwell.
Answer: a

i choose c

A正确：printer的销量增加，由于它的printer只能采用自己的墨盒，所以，虽然printer的价格降低，但仍然有可能通过销售出去更多的墨盒而比以前更挣钱，所以这就weaken了结论。

C错误：其他厂商的printer的价格更低，无法对文章的结论起到削弱作用。

C is irrelevant. Let me give you an example: A's salary is cut, therefore A's total income must be less. You can argue by saying B's income is cut even more because the original argument is not about comparing A and B. Back to the question. If the conclusion is that the company must be worse than other companies, C will be relevant.

CR requires you stick to what is within the logic reasoning of the argument.

多谢大侠相助。

多谢！

C The meaning of last sentence of this question is confusing. "the ink.... providing...with much smaller than it used to. What does the ink jet division provide, anyway? Please help with this!

这里是纵向比较,即自己和自己比.C是横向比较,和别的公司比.所以无关.