一题逻辑题：For similar cars and drivers, automobile insurance for collision damage ha

yunduanxw · 发表于 2011-11-26 14:48:16

For similar cars and drivers, automobile insurance for collision damage has always cost more in Greatport than in Fairmont. Police studies, however, show that cars owned by Greatport residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont. Clearly, therefore, insurance companies are making a greater profit on collision-damage insurance in Greatport than in Fairmont.

Which of the following is an assumption on which the argument depends?
A. Repairing typical collision damage does not cost more in Greatport than in Fairmont.
B. There are no more motorists in Greatport than in Fairmont.
C. Greatport residents who have been in a collision are more likely to report it to their insurance company than Fairmont residents are.
D. Fairmont and Greatport are the cities with the highest collision-damage insurance rates.
E. The insurance companies were already aware of the difference in the likelihood of collisions before the publication of the police reports.

答案都说是A：我也能理解，但是我认为这个答案是有问题的
我的推理过程如下：

For similar cars and drivers, automobile insurance for collision damage has always cost more in Greatport than in Fairmont.
以下的假设是满足了题目的要求的，即：
Greatport = G 单车保费：150
Farimont = F 单车保费：100

residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont.
以下的假设是满足了题目的要求的，即：
Greatport = G 有10辆车 be involved in collision的车有1辆出险率是10%
Farimont = F 有10辆车 be involved in collision的车有2辆出险率是20%

假设A是答案：
我们取反：Repairing typical collision damage does not cost more in Greatport than in Fairmont.
Greatport = G 单车陪费：12
Farimont = F 单车陪费：10

结论：
Greatport = G profit = 10*150 – 1*12 = 1476
Farimont = F profit = 10*100 – 2*10 = 980

很明显G的利润1476 > F的利润980

取反后，还是没有颠覆原文的结论：insurance companies are making a greater profit on collision-damage insurance in Greatport than in Fairmont.

只有取反后，颠覆原文结论才能是原文的隐含假设，现在取反后，原文结论依然成立，所以A是不对的。可全世界的人都说A是正确答案，连manhattangmat的大师RonPurewal也是这么说的：
the problem takes "less likely to be involved in a collision" and treats it as equivalent to "less money paid out in collision claims". (they must be making this connection in order to reach the given conclusion re: profit.)
the assumption in choice (a) is necessary for us to make this connection. i.e., if there's a possibility that greatport's accidents are more destructive (and therefore more expensive) than fairmont's, then the connection is severed and the argument no longer works.

我的推理错在哪里呢？请高手解答一下！谢谢！

yunduanxw · 发表于 2011-11-26 17:29:47

自己顶！

yunduanxw · 发表于 2011-11-27 14:05:24

自己顶！

yunduanxw · 发表于 2011-11-27 14:05:35

自己顶！

qiuhua01234567 · 发表于 2011-11-27 15:45:25

（1）：答案是B，请自己去翻,OG12 CR27 P552，你下面推论的都是按照B来推论。
（2）：residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont.
以下的假设是满足了题目的要求的，即：
Greatport = G 有100辆车 be involved in collision的车有19辆出险率是19%
Farimont = F 有10辆车 be involved in collision的车有2辆出险率是20%
个人觉得你是把这句理解错了，on average.不是百分比，百分比和平均数是不同的。个人感觉你基数一定要相等吧，不可能一个100辆，一个10辆。并且不能用百分数的形式来考虑。OG逻辑题最容易搞的就是百分比形式，平均数形式。
（3）单车陪费差距夸张，虽然是小瑕疵，但是这是实际问题，再怎么考虑都不可能有这么夸张的单车陪费吧。
总结：你取的都是极端情况，极端情况就有可能出现极端结果。还有，一道CR而已，不用考虑那么多，要知道人家的脑子比我们简单很多，你要想想你在学高数的岁数人家还在学1+1.不可能有这么复杂的逻辑。

yunduanxw · 发表于 2011-11-27 20:12:59

（1）：答案是B，请自己去翻,OG12 CR27 P552，你下面推论的都是按照B来推论。
（2）：residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont.
以下的假设是满足了题目的要求的，即：
Greatport = G 有100辆车 be involved in collision的车有19辆出险率是19%
Farimont = F 有10辆车 be involved in collision的车有2辆出险率是20%
个人觉得你是把这句理解错了，on average.不是百分比，百分比和平均数是不同的。个人感觉你基数一定要相等吧，不可能一个100辆，一个10辆。并且不能用百分数的形式来考虑。OG逻辑题最容易搞的就是百分比形式，平均数形式。
（3）单车陪费差距夸张，虽然是小瑕疵，但是这是实际问题，再怎么考虑都不可能有这么夸张的单车陪费吧。
总结：你取的都是极端情况，极端情况就有可能出现极端结果。还有，一道CR而已，不用考虑那么多，要知道人家的脑子比我们简单很多，你要想想你在学高数的岁数人家还在学1+1.不可能有这么复杂的逻辑。

-- by 会员 qiuhua01234567 (2011/11/27 15:45:25)

（2）：residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont.
以下的假设是满足了题目的要求的，即：
Greatport = G 有100辆车 be involved in collision的车有19辆出险率是19%
Farimont = F 有10辆车 be involved in collision的车有2辆出险率是20%
个人觉得你是把这句理解错了，on average.不是百分比，百分比和平均数是不同的。个人感觉你基数一定要相等吧，不可能一个100辆，一个10辆。并且不能用百分数的形式来考虑。OG逻辑题最容易搞的就是百分比形式，平均数形式。
答：在此处我的比较方式就是按照平均数来的，所以我才会列出百分比的，其实在这个语境中，百分比就是平均数，这个应该是没有质疑的。
退一步，按你的说法，我把基数搞成一样，
Greatport = G 有10辆车 be involved in collision的车有1辆出险率是10%
Farimont = F 有10辆车 be involved in collision的车有2辆出险率是20%

Greatport = G profit = 10*10000 – 1*15 = 99985
Farimont = F profit = 10*100 – 2*10 = 980

G的利润99175 仍然> F的利润980

（3）单车陪费差距夸张，虽然是小瑕疵，但是这是实际问题，再怎么考虑都不可能有这么夸张的单车陪费吧。

答：这种夸张是为了凸显效应，我就不夸张地来推：

For similar cars and drivers, automobile insurance for collision damage has always cost more in Greatport than in Fairmont.
以下的假设是满足了题目的要求的，即：
Greatport = G 单车保费：150
Farimont = F 单车保费：100

residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont.
以下的假设是满足了题目的要求的，即：
Greatport = G 有10辆车 be involved in collision的车有1辆出险率是10%
Farimont = F 有10辆车 be involved in collision的车有2辆出险率是20%

假设A是答案：
我们取反：Repairing typical collision damage does not cost more in Greatport than in Fairmont.
Greatport = G 单车陪费：12
Farimont = F 单车陪费：10

结论：
Greatport = G profit = 10*150 – 1*12 = 1476
Farimont = F profit = 10*100 – 2*10 = 980

很明显G的利润1476 > F的利润980

取反后，还是没有颠覆原文的结论：insurance companies are making a greater profit on collision-damage insurance in Greatport than in Fairmont.

yunduanxw · 发表于 2011-11-27 21:35:35

顶！

sdcar2010 · 发表于 2011-11-27 22:18:08

A is the answer.

Profit = Insurance premium - repair cost.

If repair cost is high, profit will be lowered.

yunduanxw · 发表于 2011-11-28 00:24:13

A is the answer.

Profit = Insurance premium - repair cost.

If repair cost is high, profit will be lowered.

-- by 会员 sdcar2010 (2011/11/27 22:18:08)

你这个公式太对了，你没看我的分析.
repair cost high 了，insurance premium 更high，你说profit be lowered or be heightened ?
题目并没有限定“insurance premium 不可以更high”

yunduanxw · 发表于 2011-11-28 21:45:11

自己顶！

本贴相关题目 GMATPrep-2008E2-CR-95 | TN-07-CR-24GMATPrep-2008E2-CR-95 |
TN-07-CR-24
TN-08-CR-7
... (EGXT)

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本贴相关题目 GMATPrep-2008E2-CR-95 | TN-07-CR-24GMATPrep-2008E2-CR-95 | TN-07-CR-24TN-08-CR-7 ... (EGXT)

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一题逻辑题：For similar cars and drivers, automobile insurance for collision damage ha

所属分类: GMAT考试

正在浏览此版块的会员 ()

本贴相关题目 GMATPrep-2008E2-CR-95 | TN-07-CR-24GMATPrep-2008E2-CR-95 |
TN-07-CR-24
TN-08-CR-7
... (EGXT)