三道逻辑题望高人指点 谢谢！

crazyshawn

1， Frobisher, a sixteenth-century Englishexplorer, had soil samples from Canada’s Kodlunarn Island examined for goldcontent.  Because high gold content wasreported, Elizabeth I funded two mining expeditions.  Neither expedition found any gold there.  Modern analysis of the island’s soilindicates a very low gold content.  Thusthe methods used to determine the gold content of Frobisher’s samples must havebeen inaccurate.

Which of the following is an assumption onwhich the argument depends?

1. The gold content of the soil on Kodlunarn Island is much lower     today than it was in the sixteenth century.
   
2. The two mining expeditions funded by Elizabeth I did not mine     the same part of Kodlunarn Island.
   
3. The methods used to assess gold content of the soil samples     provided by Frobisher were different from those generally used in the     sixteenth century.
   
4. Frobisher did not have soil samples from any other Canadian     island examined for gold content.
   
5. Gold was not added to the soil samples collected by Frobisher     before the samples were examined.
   

这道题答案是选的E  不明白答案是什么意思，请高人指点

2， Q19:
In Rubaria, excellent health care isavailable to virtually the entire population, whereas very few people inTerland receive adequate medical care. Yet, although the death rate for most diseases is higher in Terland thanin Rubaria, the percentage of the male population that dies fromprostate cancer is significantly higher in Rubaria than in Terland.

Which of the following, if true, most helpsto explain the disparity between the prostate cancer death rate in Rubaria andTerland?

A.    Effective treatment of prostate cancer inits early stages generally requires medical techniques available in Rubaria butnot in Terland.
B.    Most men who have prostate cancer are olderthan the average life expectancy for male inhabitants of Terland.
C.    Being in poor general health does notincrease one’s risk of developing prostate cancer.

1. It is possible to decrease one’s risk of getting prostate     cancer by eating certain kinds of foods, and such foods are more readily     available in Rubaria than in Terland.
   
2. Among men in Rubaria, the death rate from prostate cancer is     significantly higher for those who do not take full advantage of Rubaria’s     health care system than for those who do.
   

这道题答案选B  我不明白得这个大多数得癌症的人年龄比这个国家的平均男子寿命老有什么关系 怎么支持文章的论点的呢？


3
Q40:
Parland’s alligator population has beendeclining in recent years, primarily because of hunting.  Alligators prey heavily on a species offreshwater fish that is highly valued as food by Parlanders, who had hoped thatthe decline in the alligator population would lead to an increase in the numbersof these fish available for human consumption. Yet the population of this fish species has also declined, even thoughthe annual number caught for human consumption has not increased.

Which of the following, if true, most helpsto explain the decline in the population of the fish species?

1. The decline in the alligator population has meant that fishers     can work in some parts of lakes and rivers that were formerly too     dangerous.
   
2. Over the last few years, Parland’s commercial fishing     enterprises have increased the number of fishing boats they use.
   
3. Many Parlanders who hunt alligators do so because of the high     market price of alligator skins, not because of the threat alligators pose     to the fish population.
   
4. During Parland’s dry season, holes dug by alligators remain     filled with water long enough to provide a safe place for the eggs of this     fish species to hatch.
   
5. In several neighboring countries through which Parland’s rivers     also flow, alligators are at risk of extinction as a result of extensive     hunting.
   

这道题答案选D， 在干燥的季节 鳄鱼挖的洞充满了足够深的水使得这种鱼的蛋可以被安全的孵化  意思是说鳄鱼在它孵化的过程中就把这个鱼的蛋吃了吗？


谢谢大家！

hughlv

1. 前提是这块样品没有被人为的添加金含量，即前提是没有造假。

sdcar2010

Q40
Parland’s alligator population has beendeclining in recent years, primarily because of hunting.  Alligators prey heavily on a species offreshwater fish that is highly valued as food by Parlanders, who had hoped thatthe decline in the alligator population would lead to an increase in the numbersof these fish available for human consumption. Yet the population of this fish species has also declined, even thoughthe annual number caught for human consumption has not increased.

Which of the following, if true, most helpsto explain the decline in the population of the fish species?

A) The decline in the alligator population has meant that fishers can work in some parts of lakes and rivers that were formerly too dangerous.
B) Over the last few years, Parland’s commercial fishing enterprises have increased the number of fishing boats they use.
C) Many Parlanders who hunt alligators do so because of the high market price of alligator skins, not because of the threat alligators pose to the fish population.
D) During Parland’s dry season, holes dug by alligators remain filled with water long enough to provide a safe place for the eggs of this fish species to hatch.
E) In several neighboring countries through which Parland’s rivers also flow, alligators are at risk of extinction as a result of extensive hunting.

这道题答案选D， 在干燥的季节 鳄鱼挖的洞充满了足够深的水使得这种鱼的蛋可以被安全的孵化  意思是说鳄鱼在它孵化的过程中就把这个鱼的蛋吃了吗？

This is a paradox question.  You need to provide a reason to explain the apparent contradiction.  In this case, the number of alligator, which preys on a type of fish, is decreasing.  One would think that since the predator (alligator) is decreasing, the prey (the fish) should flourish or at least keep steady.  However, the stimulus claims that the prey's number is decreasing, hence the paradox.

Answer D says that decreasing number of alligator also decreases the safe places for the fish eggs to hide.  If the eggs hatched decrease, the amount of fish in the next generation will shrink.  This explanation links perfectly the decrease of predator and that of the prey, hence reconciles the paradox.

hughlv

2. T的男人们在得癌症的平均年龄前就死翘了，这是为什么T得癌症的人比较少的原因

crazyshawn

Thanks for your solution, however i am still confused with NO.1 and NO.2 questions. Could you explain more about how  does the reasoning for those two questions work?

hughlv

第一题的大意：16世纪通过对一块来自特定地区的石头样本的检测得出该石头含金量很高。这个检测报告导致了女王同志在那个地区投资了两个金矿结果却血本无归。用当代的检测方法发现其实那块土地其实含金量很低。得出的结论是早先的检测方法不准确。

得出错误结论的原因有两个：1）被检测材料，2）检测方法。

本文中认定检测方法有问题，也就是假设被检测材料没有问题。E对应这个假设：那块石头样本没有被人为的提高金含量。因为如果这块石头被造假了，那么原来的检测方法没问题也会导致检测结果有问题。

hughlv

2. R拥有比T好很多的医疗服务。T的大多数疾病死亡率要高于R，但是R的P癌症死亡率却比T高很多。问原因。

按常理，同样一个人得P癌症，在R应该有更大的机会治愈。选项B给出了对于数字的一个有效解释，即T的男性平均寿命要低于开始的P癌症的年龄。比如一般人都是70岁得P癌症，但是T的男性都只活到65(life expectancy)，那自然就一个人都不得P癌症了。因此这并不表示R的医疗服务没用，而是T的医疗服务需要改进以提高平均寿命。

crazyshawn

thanks!