请原谅我哪些钻牛角尖的题目。。T,T 感激。。

yiayia

We now see the only thing happening is that  a low-pressure weather system is approaching Plainville. It is the only information that we base on to make the inference.   Then the argument tells us two conditions. You have to figure out what is the meaning of "result from".
If we translate it into the maths words, it should be presented in this way:
l=low pressure
t=thundershowers
r=rainfall
That is P(r)/P(l)=70% if l happens, the probability of r is 70%. The stimulus asks us p(t)/p(l)=?
B tell us that P(t)/p(r)=?  
So if we multiply these two percentage, we actually can judge the probability that Plainville will have a thundershower.
Let's check the answer C. I have read the reasoning in the feifei logic. It is totally wrong. C told that P(l)/P(t)=?  However，we cannot simply reverse the percentage. For example,   P(l)/P(t)= 50%, and then the reversed percentage P(t)/P(l)= 200%. How can it be possible?

If we jump out of the scope of "maths", we can eliminate C because there maybe other reasons for a thundershower. We can say the probability that Plainville will have a thundershower soon after knowing a low-pressure weather system is 100%. But because of others causes, the thundershowers are not all caused by  low-pressure weather systems. Thus the percentage of thundershowers in Plainville that result from low-pressure systems is 50%. As far as we can see, this choice is not "strict" enough.

The right answer is B. You have done a great job, and just believe yourself.

babybearmm

Just add my 2c
This question is about conditional probability （条件概率）。
Question: p(R|L)=70%, p(T|L)=?
Choice B: p(R|T) is known
Choice C: p(L|T) is known
....

I like yiayia's intuitional thought:
"For example,   P(l)/P(t)= 50%, and then the reversed percentage P(t)/P(l)= 200%. How can it be possible?"
"If we jump out of the scope of "maths", we can eliminate C because there maybe other reasons for a thundershower. "

199249712

GWD-10-Q30:GWD-2-17
Thequality of unrefined olive oil is not actually defined in terms of acidity, yet extensive testshave shown
that the less free oleic acid an unrefined olive oil contains perliter, the higher its quality.  
Theproportion of free oleic acid that an olive oil containsis an accurate measure of the oil’s acidity.

If the statements aboveare all true, which of the following conclusions is best supported by them?

A.     When an olive oil is refined, the concentrationof oleic acid in the oil is reduced.
B.     The quality of an unrefined olive oil can be determinedonly by accurately measuring its acidity.
C.      If an unrefined olive oil is intermediate in aciditybetween two other unrefined olive oils, it will also be intermediate betweenthem in quality.
D.     Free oleic acid is the only acid that unrefined olive oilcontains.
E.      People who judge the quality of unrefined olive oilsactually judge those oils by their acidity, which the judges can taste.




一道诡异的争议题0 0

偶感觉是A耶。。。 因为C说的酸不是free acidity啊。。。
我中和酸性也可能把别的酸掺进来了。。。

但是A也有问题 A说的是 an olive oil is refined
题目说的是 unrefined olive

T.T

199249712

关于因果型//条件型结论

babybearmm

“因为C说的酸不是free acidity啊。。。”
The stimulus says, "The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity. "
In mathematical term, it means that:
(oil's acidity) = k * (% of free oleic acid)
, in which k is the coefficient.

"我中和酸性也可能把别的酸掺进来了。。。"
你理解错了，题目没有涉及任何酸碱中和反应

“但是A也有问题 A说的是 an olive oil is refined 题目说的是 unrefined olive ”
Exactly!

GWD-10-Q30:GWD-2-17
Thequality of unrefined olive oil is not actually defined in terms of acidity, yet extensive testshave shown
that the less free oleic acid an unrefined olive oil contains perliter, the higher its quality.  
Theproportion of free oleic acid that an olive oil containsis an accurate measure of the oil’s acidity.

If the statements aboveare all true, which of the following conclusions is best supported by them?

A.     When an olive oil is refined, the concentrationof oleic acid in the oil is reduced.
B.     The quality of an unrefined olive oil can be determinedonly by accurately measuring its acidity.
C.      If an unrefined olive oil is intermediate in aciditybetween two other unrefined olive oils, it will also be intermediate betweenthem in quality.
D.     Free oleic acid is the only acid that unrefined olive oilcontains.
E.      People who judge the quality of unrefined olive oilsactually judge those oils by their acidity, which the judges can taste.




一道诡异的争议题0 0

偶感觉是A耶。。。 因为C说的酸不是free acidity啊。。。
我中和酸性也可能把别的酸掺进来了。。。

但是A也有问题 A说的是 an olive oil is refined
题目说的是 unrefined olive

T.T

-- by 会员 199249712 (2012/4/2 14:58:29)

199249712

谢谢姐姐 我明白了………… 我怕你要睡了没敢信息你 结果姐姐来看偶帖子了。。
你那很晚了啊。。。 好刻苦。。~！！

199249712

T-3-Q32.

A theory is either true or false. Galileo’sobservations of Jupiter’s satellites showed that the Ptolemaic theory of themotion of celestial bodies is false. Therefore, since the Copernicantheory of planetary motion is inconsistent with the Ptolemaicaccount, Galileo’s observations of Jupiter’s satellites proved the truth of theCopernican theory.

The argument above is open to the objection that itmakes the questionable assumption that

A.     Whoever first observed something inconsistent with thetruth of the Ptolemaic theory should be credited with having proved that theoryfalse.

B.     There are some possible observations thatwould be inconsistent with the account given by the Copernican theory butconsistent with the account given by the Ptolemaic theory.

C.     The Ptolemaic and Copernican theories,being inconsistent, cannot both be based on exactly the same evidence

D.     Numerous counterexamples were necessary inorder to show the Ptolemaic theory to be false

E.       The Ptolemaic and Copernican theories,being inconsistent, cannot both be false.

偶是一个粗心的孩子。。。偶为什么没看见first呢 = =

babybearmm

This is a good example of the logical error called "false dilemma".

199249712

One of the most effective techniques for quickly finding correct answer choices and avoiding incorrect answer choices is prephrasing. Prephrasing an answer involves quickly speculating on what you expect the correct answer will be based on the information in the stimulus.

199249712

艾玛从一个自习室被赶到另一个自习室- -|||烦死了都
1、刷了25到CR
2、做了阅读小分队
3、看陈向东数学。。。看了34页吧。。。- - 全是小学奥数题。。作为一个深恶痛绝奥数且偏科的孩子 我表示数学很无力
4、做做语法。。看看错题。。。

未完成：
1、看bible
- -完全不想看bible。。。
搜点新文章来看 不知道GMAT的阅读速度要求是多少啊？？