请教大全5－19

深海的小美人鱼

19.    Recent estimates predict that between 1982 and 1995 the greatest increase in the number of people employed will be in the category of low-paying service occupations. This category, however, will not increase its share of total employment, whereas the category of high-paying service occupations will increase its share.
If the estimates above are accurate, which of the following conclusions can be drawn?
(A) In 1982 more people were working in low-paying service occupations than were working in high-paying service occupations.
(B) In 1995 more people will be working in high-paying service occupations than will be working in low-paying service occupations.
(C) Nonservice occupations will account for the same share of total employment in 1995 as in 1982.
(D) Many of the people who were working in low-paying service occupations in 1982 will be working in high-paying service occupations by 1995.
(E) The rate of growth for low-paying service occupations will be greater than the overall rate of employment growth between 1982 and 1995.
B为什么不对？

snow_mountain

B是不对的。 举个例子|：low paying 的share 可以一直是20％。 可是high paying 可以从5％长到10％。

我用排除法做出A。 但是也不是很明白A为什么对？哪位给指点一下？

snow_mountain

A也想明白啦。归根到底吃的数学不好的亏。

睡熊

宏观上分析：变化后两个元素如果保持同样的比重，两个元素必须按照相对原来自身同样的比例变化；如果一个元素的绝对变化超过另外一个元素的绝对变化，而两者在总量中的比例变化的方向相反，则第一个元素的初始量一定大于第二个元素的初始量。

微观上分析：
[attachimg]10842[/attachimg]

睡熊

(B) 跟事实正好相反。

snow_mountain

感谢睡熊的理论分析。

番茄炒蛋

呵呵，真是一个很好玩的数学题
仔细想想应该就能想通的，就是一个关于基数的问题

flora_wang

大全 test 2 也是这类问题.就是增长幅度和占总的比例关系
10.    This year the New Hampshire Division of Company X set a new record for annual sales by that division. This record is especially surprising since the New Hampshire Division has the smallest potential market and the lowest sales of any of Company X’s divisions.
Which of the following identifies a flaw in the logical coherence of the statement above?
(A) If overall sales for Company X were sharply reduced, the New Hampshire Division’s new sales record is irrelevant to the company’s prosperity.
(B) Since the division is competing against its own record, the comparison of its sales record with that of other divisions is irrelevant.
(C) If this is the first year that the New Hampshire Division has been last in sales among Company X’s divisions, the new record is not surprising at all.
(D) If overall sales for Company X were greater than usual, it is not surprising that the New Hampshire Division was last in sales.
(E) Since the New Hampshire Division has the smallest potential market, it is not surprising that it had the lowest sales.

flora_wang

答案是b