北美11月28放狗。。大家可以来看看逻辑

tancywang

发出来积累RP，12月一定要一次过！！！！！

数学只有49。。。参考意义不大

Is |x-y|> |x-z|？

1.|y|>|z|

2.x<0

我选了C 答案应该是E

an=a（n-1）+3，问a100-1能否被3整除？

1.a1能被3整除

2.a99 _不能_被3整除

我选的A

男投票人里47%投了x，女投票人里52%投了x，问总共投x的人有没有超过50%

1.很无关的选项

2.女性投票人more than50%

（我一直在纠结第二个…最后选了E 因为大于50%的话，女性投x可以26，男性可以23 就等于50%…现在想来觉得应该是B单独就充分吧。。希望有大神解答一下）

阅读：

第一篇讲了food preparation。。

第二篇是sun起源的cluster，是不是和某些星星一样之类的…这篇真的太长了  大家一定要看jj 我没看jj做的要崩溃了

逻辑：

很多航天员反映说火箭的椅背之类的坐的非常不舒服 但已经用了很好的材料，需要怎么改进之类的…某个科学家说，这不是材料问题而是concept的问题。

问推断还是加强…

我选的是A. 人只有在长期不坐着的时候才会不难受

有一个mall里面进了很多新的卖衣服的店，所以导致所有卖衣服的店sales都降低了，所以mall决定限制mall里面卖衣服店的数量，把其他的space都来卖生活用品，可是卖衣服的店sales还是没有变多？

问possible解释：

有很多干扰项，

不过我选的是D/E 旁边新开了个mall里面有很多卖衣服的店

一个城市发现自己的水源被污染了，人们如果吃了被感染的鱼就会生病，于是城市决定用xx system来实时检测水源，所以当人们想知道自己生活的水源污染有没有加重时，只需要看水源周围有没有设立xx system检测就好了。

问削弱

这题我选的答案忘了。。。

大概率我选的是，一经检测只要有污染后，污染会持续很多年 （不太确定）

一种病是通过在海里游泳感染xx病毒传染的，不过人们用一种检测仪仪可以很好的检测出来这种病菌，但这种检测仪在beach边上用会失灵，所以科学家决定换一种方法，只检测某些健康的细菌。

问加强还是解释我忘了。。。

我选的是，当有这些好的细菌时候，xx病毒就会存在

大家大概可以相信我的逻辑。。我买了个esr看 analysis是100%

sc就不说了。。。做的时候觉得很确定 看esr惊呆了grammar42% communication80% 跪求大家有什么能快速提高sc的方法！！

GMAT上上上

谢谢，可是JJ里的sun cluster也没几句话，都说这篇好难

billyisfragile!

男投票人里47%投了x，女投票人里52%投了x，问总共投x的人有没有超过50%

1.很无关的选项

2.女性投票人more than50%

（我一直在纠结第二个…最后选了E 因为大于50%的话，女性投x可以26，男性可以23 就等于50%…现在想来觉得应该是B单独就充分吧。。希望有大神解答一下）

If 女性投票人=51%

	male	female
vote	0.49t*0.47 = 0.2303t	0.51t*0.52 = 0.2652t	0.4955t < 50%
not vote
	0.49t	0.51t	total = t

If 女性投票人=99%

	male	female
vote	0.01t*0.47 = 0.0047	0.99t*0.52 = 0.5148t	0.5195t > 50%
not vote
	0.01t	0.99t	total = t

billyisfragile!

GMAT上上上 发表于 2019-11-30 09:31
谢谢，可是JJ里的sun cluster也没几句话，都说这篇好难

https://www.scientificamerican.com/article/the-long-lost-siblings-of-the-sun/

The Long-Lost Siblings of the Sun
The sun was born in a family of stars. What became of them?

By Simon F. Portegies Zwart on November 1, 2009

IN BRIEF

● The sun is a solitary star, and astronomers have traditionally assumed it formed as such. Yet most stars are born in clusters, and scraps of evidence from meteorites and from the arrangement of comets suggest that our sun was no exception.
● Its birth cluster could have contained 1,500 to 3,500 stars within a diameter of 10 light-years—a big, unhappy family whose larger members bullied the small fry and which broke up not long after our solar system came into being.

Although the sun’s siblings have long since dispersed across the galaxy, observatories such as the European GAIA satellite will be able to look for them. Their properties might fill in the gaps of the solar system’s deep history.

People have often sought solitude in the starry night sky, and it is an appropriate place for that. The night is dark because, in cosmic terms, our sun and its family of planets are very lonely. Neighboring stars are so far away that they look like mere specks of light, and more distant stars blur together into a feeble glow. Our fastest space probes will take tens of thousands of years to cross the distance to the nearest star. Space isolates us like an ocean around a tiny island.

Yet not all stars are so secluded. About one in 10 belongs to a cluster, a swarm of hundreds to tens of thousands of stars with a diameter of a few light-years. In fact, most stars are born in such groups, which generally disperse over billions of years, their stars blending in with the rest of the galaxy. What about our sun? Might it, too, have come into existence in a star cluster? If so, our location in the galaxy was not always so desolate. It only became so as the cluster dispersed in due time.

A growing body of evidence suggests just that. Although conventional wisdom once held that the sun was an only child, many astronomers now think it was one of 1,000 or so siblings all born at nearly the same time. Had we been around at the dawn of the solar system, space would not have seemed nearly so empty. The night sky would have been filled with bright stars, several at least as bright as the full moon. Some would have been visible even by day. Looking up would have hurt our eyes.

The cluster into which the sun was probably born is now long gone. I have pieced together the available data and made an educated guess as to what it might have looked like. From these inferred properties, I have calculated the possible trajectories of former cluster members through the galaxy to figure out where they might have ended up. Although they have scattered and mixed in with millions of unrelated stars, they should be identifiable with the European Space Agency’s Global Astrometric Interferometer for Astrophysics (GAIA) satellite, scheduled for launch in 2011. Their orbits and sunlike compositions should give them away. Reuniting with our long-lost stellar siblings should enable astronomers to reconstruct the conditions under which a shapeless cloud of gas and dust gave rise to our solar system.

Memories of Our Birth

现在科学家对研究的两块太阳早期落在地球上的陨石(meterorite)进行样本化验：里面含有镍60(nickel)成分。
镍60(nickel)是一种铁60(iron)衰变(decay)后的产物。(Q4)

The most compelling evidence that the sun has close siblings emerged in 2003, when Shogo Tachibana, now at the University of Tokyo, and Gary R. Huss, now at the University of Hawaii at Manoa, analyzed two primitive meteorites that are thought to be almost pristine leftovers of solar system formation. They detected nickel 60, the product of the radioactive decay of iron 60, in chemical compounds where, by rights, iron should be found. It seems a game of chemical bait and switch took place in the meteorite: the compounds originally formed from iron, the iron metamorphosed into nickel, and the nickel was locked in place, forever an interloper.

那么就推论说这种物质的形成可能是在太阳1.8 billion岁的时候five (可能有个倍数词) light years的距离中有个星星自爆产生的。

The iron 60 had to be synthesized, injected into the solar system and incorporated into meteorites within its radioactive half-life, which, according to a new estimate published this past August, is 2.6 million years. That is a cosmic eyeblink. Therefore, the iron had to come from very nearby—and the likeliest source is a supernova explosion. Based on this and other isotopic measurements, Leslie Looney of the University of Illinois and his co-workers argued in 2006 that a supernova went off within a distance of five light-years when the sun was scarcely 1.8 million years old. The supernova might have been as close as 0.07 light-year. (The new half-life estimate will change these values, but not substantially.)

P2：证据一，支持论点。
现在科学家对研究的两块太阳早期落在地球上的陨石(meterorite)进行样本化验：里面含有镍60(nickel)成分。
镍60(nickel)是一种铁60(iron)衰变(decay)后的产物。(Q4)
但转变过程需要一定条件。而太阳系附近不怎么可能有这样的条件(had been secluded)，所以太阳很可能在很久以前是跟某个超新星在一个cluster里，这个cluster应该在银河核心(galaxy center)。一般来说，当恒星(star)离这个中心越近，这种重金属含量越多(rich)。

If the sun had been as secluded as it is today, the location and timing of the supernova would be quite a coincidence. Was a massive star simply passing by when it decided to blow up? No other supernova has ever gone off at such close range; if it had, it would probably have wiped out life on Earth. A much more plausible explanation is that the newborn sun and the exploding star were fellow members of a cluster. With stars packed so tightly together, a close supernova would not have been so improbable.

GMAT上上上

bzy! 发表于 2019-11-30 09:53
男投票人里47%投了x，女投票人里52%投了x，问总共投x的人有没有超过50%1.很无关的选项2.女性投票人more tha ...

我看了下之前的寂静，数讨菌举的例子是 男100 女101

dilysqiu0724

感谢CR的分享！！！

billyisfragile!

GMAT上上上 发表于 2019-11-30 10:53
我看了下之前的寂静，数讨菌举的例子是 男100 女101

男投票人里47%投了x，女投票人里52%投了x，问总共投x的人有没有超过50%
1.很无关的选项
2.女性投票人more than50%

DS：说参加选举的人数，男性中参加选举的占男性的47%，女性中参加选举的占女性的52%，问能不能判断参加选举的人数超过总人数的一半？
条件1：忘了
条件2：女性占总人数的50%以上
构筑：也忘了选了啥= =

一个选举投票，男性有47%的人支持这个candidate,女性有52%的人支持这个candidate ，问支持率超过一半吗
条件1 男性人数多于50%，女性人数少于50%
条件2 不记得了

DS：是否有>50%的人选了C？
条件1：男：47%选C，女：52%选C；
条件

男的有47％支持了某人，女的有52％支持了某人，问是否有超过50％的总体国民支持了某人
1）男人和女人的数量差
2）女人数量占总体国民的50％以上2：选C有超过一半是女的
为选举的人是不是超过1/2
(1）男的里面有47% 选举, 女的里面有52%选举；
(2)   女的比例超过50%
我选了C

说某国选举，男的有47％支持了某人，女的有52％支持了某人，问是否有超过50％的总体国民支持了某人
1）不记得了，好像是男人和女人的数量差
2）女人数量占总体国民的50％以上
选B, 不确定

选举Ｘ人是否超过半数，女投票者中选Ｘ的占５２％，男投票者中选Ｘ的占4７％．
１．女的人数超过半数
２．男的人数不少于50％

问是否有超过50％的总体国民支持了某人
  1）男的有47％支持了某人，女的有52％支持了某人，
  2）女人数量占总体国民的50％以上
注意，这题的条件和问法跟JJ里的题略有不同
答案：E

何志武

楼主可以贴下SC/CR/RC三个正确图的那个图吗？想参考下你的CR~感谢分享！！

要努力的水晶

感谢分享！               

轩嘉尘然

谢谢楼主分享！我想问一下楼主考后多久出的esr鸭，我29上午考完到现在还没出