[分享]讨论lsat !!!!

greandgmat

欢迎和我一起讨论lsat 我已经做了三遍了
水平在50分钟错2-5题
反正就是每道题都熟得不行了

i ll take the test 31oct in bj（3rd time)
希望在北京的朋友一起交流：）

madeleinerao[在] yahoo.com

ninishine

thank you for offering help. I have a problem to discuss.
. Most parents who are generous are good parents, but some self-centered parents are also good parents. Yet all good parents share one characteristic; they are good listeners.
If all of the statements in the passage are true, which one of the following must also be true?
(A) All parents who are good listeners are good parents.
(B) Some parents who are good listeners are not good parent.
(C) Most parents who are good listeners are generous.
(D) Some parents who are good listeners are self-centered
(E) Fewer self-centered parents than generous parents are good listeners.

the answer is D. but I'm confused and don't know why. could you please show me how whould you think about this kind of question? thank you very much!

greandgmat

着是一个充分必要条件的提
只要知道一个命题的逆否等于 他 的 原命题就可以了
很简单的 ：）

lilyhuang

Sec 4 ( III)
12. The number of North American children who are obese- that is who have more body fat than do 85 percent of North American children their age - is steadily increasing, according to four major studies conducted over the past 15 year.

If the finding reported above is correct, it can be properly concluded that
(A) when four major studies all produce similar results, those studies must be accuraate.
(B) North American children have been prograssively less physically active over the past 15 years.
(C) The number of North American children who are not obese increased over the past 15 year.
(D) Over the past 15 years, the number of North American children who are underweight has declined.
(E) The incidence of obosity in North American children tends to increase as the children grow older.

A，B，D，E有很明显的错误. 无论如何不明白C为什么是对的, 脑子好象糊涂了. Can you give me some tips? Many thanks.

greandgmat

这是一个数学问题
纯粹计算：
胖的人增多了。胖的人=85% *总人数
                     瘦的人 =25% *总人数
胖子 多了说明 总人数 多了
总人数多了 推出 瘦人多了

greandgmat

to ninishine
那种题画韦恩图最快

lilyhuang

Thank u.

greandgmat

to lilyhuang
do you see what i mean in the explaination?do you agree ?
you are very welcom

lilyhuang

"that is who have more body fat than do 85 percent of North American children their age"
D) Over the past 15 years, the number of North American children who are underweight has declined.

Sorry, i didn't carefully check the answer in a hurry yesterday.  But in D choice, it means that the number of...... has declined, not"increased".  On the other hand, the children described in the paragraph should be divided into three categories: children who are obese, children who are at normal weight, children who are underweight. I really don't know how to reason to get D choice???

antoine

请教这位大牛一题,应该对你来说是很简单的.

22. It is illogical to infer a second and different effect from a cause which is known only by one particular effect. This is incorrect because the inferred effect must necessarily be produced by some different characteristic of the cause than is the observed effect, which already serves entirely to describe the cause.

Which one of the following arguments makes the same logical error as the one described by the author in the passage?

(A) An anonymous donor gave a thousand dollars to our historical society. I would guess that that individual also volunteers at the children’s hospital.

(B) The radioactive material caused a genetic mutation, which, in turn, caused the birth defect. Therefore, the radioactive material caused the birth defect.

(C) The tiny, unseen atom is the source of immense power. It must be its highly complex structure that produces this power.

(D) The city orchestra received more funds from the local government this year than ever before. Clearly this administration is more civic-minded than previous ones.

(E) If I heat water, which is a liquid, it evaporates. If I heat hundreds of other liquids like water, they evaporate. Therefore, if I heat any liquid like water, it will evaporate