2.8 裤头，放小狗

vicky780

Q50 V36 IR8 - Total 720
楼主美本，从决定考研到报名GMAT再到考试一共23天的时间，其中一半时间全职，接触CD也不过10天，之前一直在用老美的app复习。
OG一共做了不到100题，抱着完全靠JJ的心态，结果昨天换裤了 国内还没开始考试，又加上是裤头，一道JJ都没有，再加上复习不充分，几乎裸考的感觉上的考场。昨晚心态真的是崩了，还好成绩出来还看得过去，来放个小狗攒人品，希望好好复习后二战可以上740。

AWA:
一家眼镜公司之前是outsource eyeglass frame的生产，cost $35/pair，好几年没盈利了。现在author建议应该改成公司自己生产，只要投入$500,000买machinery和再雇一个员工，公司就可以自己生产fram，cost是$25/pair。author说改成自己生产is the best way to allocate financial resources and gain profit in the next couple years.

Quantitative:
- (3!+4!)! 结尾有几个零
- 老师点名，三个名册，A科目上有18人，B有18人，C有*人，有9人同时上AB，9人同时上BC，*人同时上AC，4人三个都上了, 问一共多少人。（*号处数字不记得了）
- DS: xy-z>x-yz?
   1: y>1
   2: x>0
还有几道特别简单的就不具体写了，一道勾股定理变体，一道测试（x²-1)=(x+1)(x-1) 这个公式

阅读:
- Bird Evolution 观点：鸟是由一种恐龙进化来的。给了三个别人的反面观点，化石出现时间，体征，前两个被驳回，最后一个说证据不充分不支持也不反驳

- European Community (EC) removal of border controls，竞争力增大，促使industrial concentration增大，部分行业的大公司持续增大，因为economies of scale，使小公司不得不离开市场。但其他的一些行业不受此影响，因为之前就已经很concentrated了，或者其他原因。

小蝦

鸟类进化 找了下 疑似考古

Although many lines of evidence indicate that birds evolved from ground-dwelling theropod dinosaurs, some scientists remain unconvinced. They argue that theropods appeared too late to have given rise to birds, noting that Archaeopteryx lithographic - the oldest known bird - appears in the fossil record about 150 million years ago, whereas the fossil remains of various nonavian maniraptor theropods - the closest known relatives of birds - date only to about 115 million years ago. But investigators have now uncovered bones that evidently belong to nonavian maniraptors dating to the time of Archaeopteryx. In any case, failure to find fossils of a predicted kind does not rule out their existence in an undiscovered deposit. Skeptics also argue that the fused clavicles (the "wishbone") of birds differ from the unfused clavicles of theropods. This objection was reasonable when only early theropod clavicles had been discovered, but fossilized theropod clavicles that look just like the wishbone of Archaeopteryx have now been unearthed. Finally, some scientists argue that the complex lungs of birds could not have evolved from theropod lungs, an assertion that cannot be supported or falsified at the moment, because no fossil lungs are preserved in the paleontological record.

Chara777

北美2.9考 感谢！！

Ameliaami

谢谢楼主！

tommxx

2.9 加油！

961025

求问楼主那个几个零的楼主选的是多少？

tommxx

961025 发表于 2019-2-9 09:03
求问楼主那个几个零的楼主选的是多少？

我想(30!)有7个5, 所以有7个零

qqtu

tommxx 发表于 2019-2-9 09:33
我想(30!)有7个5, 所以有7个零

同意思路。但是不应该是6个0吗？
5, 10, 15, 20, 25, 30

tommxx

qqtu 发表于 2019-2-9 09:37
同意思路。但是不应该是6个0吗？
5, 10, 15, 20, 15, 30

25有两个5.  5 10 15 20 25 (5*5) 30

痴人也有梦

961025 发表于 2019-2-9 09:03
求问楼主那个几个零的楼主选的是多少？

这种题目的解题思路：
n!求0
n/5=a
n/25=b
n/125=c
....就是5的x次方
然后相加就是结果了

30!=30/5+30/25=6+1=7
120!=120/5+120/25=24+4=28
172!=172/5+172/25+172/125=34+6+1=41

qqtu

tommxx 发表于 2019-2-9 09:53
25有两个5.  5 10 15 20 25 (5*5) 30

谢谢解惑！