[1006G]xiaoyaozi5566的GRE数学解题站

susuyaaUID: 2324593

(9504)几道题请教，谢谢！
SECTION 3
24,25图表题

27.
The measures of two angles of a parallelogram differ by 52 degrees.
The number of degrees in the smaller angle is
(A) 38
(B) 52
(C) 64
(D) 76
(E) 128

解答：
re楼下，我没那些图表，就解答你这道27题吧！
这题说的是，平行四边形的两个角相差52度，也就是，大角-小角=52，然后，又因为平行四边形大角+小角=180
so，两个方程相减，得小角=（180-52）/2=64
答案选C
by xiaoyaozi

无敌小番茄UID: 2684290

16# susuyaa
LS 直接把图表发上来吧
估计楼主都没有那些题目了

zyuan12UID: 2625480

The measures of two angles of a parallelogram differ by 52 degrees.
number of degrees in the smaller angle is

parallelogram 是平行四边形
其两个角的和为180
A+B=180  A-B=52
求比较小的那个角
应该是64

(PS：我有点闲的无聊...  所以进来看看...
算了, 我觉得我还是去做填空好了...第一遍都没做完
时间不够还瞎晃是不对的)

susuyaaUID: 2324593

[quote] 16# susuyaa  
LS 直接把图表发上来吧
估计楼主都没有那些题目了
无敌小番茄 发表于 2009-10-9 08:18 [/quote   ]


24. The electricity used by the water heater was
measured separately and its cost per kilowatt-hour was
one-half the cost per kilowatt-hour of the rest of the
electricity used. The cost of the electricity used by the
water heater was most nearly what fraction of the total
cost of all the electricity used?
(A)1/11
(B)1/9
(C)1/8
(D)1/5
(E) It cannot be determined from the information given.

25. In November the Smythe household used the same
total amount of electricity as in July, but the water
heater used 33 percent of this total amount. By
approximately what percent did the amount of
electricity used by the water heater increase from July
to November?
(A) 13%
(B) 33%
(C) 50%
(D) 65%
(E) 130%
我把图贴上来了，谢谢解答的各位〜

解答：
第24题，说的是热水器的电的价格是其他的用电的价格的一半，因此，我们假设一共用了100度电，每度电1块钱（热水用电每度电5毛钱），那么热水用了20度电，就是10块，然后总共是90块，因此热水器用的电的cost占的比例为1/9，选B

第25题，7月用了20%，11月用了33%，因此11月用的：7月用的=33/20=165%（因为两个月总量相同），所以，增加的用电量为65%，选D

by xiaoyaozi

wy3s1UID: 2708794

我也来问个题啊
  the figure above show a rectangular play area in which  one child stands at B while another chid runs back and forth al0ng the entire side AD. if the running child is in a position randomly located along side AD at a given time, what is the probabiiy that the two children are at most 50 feet apart at that time

A   1/5
B   2/5
C 3/5
D 4/5
E 1
   谢谢啊  是黄皮书里的     对了啊 那个矩形 AD =50 feet   AB =30 feet
解答：
见图：
黑点表示不动的小孩，红点表示运动的小孩，红色小孩在AD上随机分布，没给出分布模型那就是均匀分布，也就是在AD上任意一点的概率相同。图中是临界情况，此时，两个小孩正好距离50，如果红色小孩在这个点的左边，那么距离就小于50；在这个点右边，那么距离就大于50
左边的长度是40，占边长的4/5，因此，他们距离小于50的可能性就是4/5
by xiaoyaozi

susuyaaUID: 2324593

(9510) 请教几题,谢谢!
SECTION 1
24. For the categories given, which category accounts for approximately 1/4of the total number of graduates expected for each off the years shown?
(A) High school diploma
(B) Associate degree
(C) Bachelor's degree
(D) Master's degree
(E) Doctoral degree

这题不了解题意?

29. When it was found that 150 more tickets for the school play were sold than the seating capacity of the auditorium. It was decided to have two performances. if the total number of tickets sold was equal to the total number who attended and if the auditorium was 2/3 full for each of the two performances, what is the seating capacity of the auditorium?
(A)100
(B)200
(C)225
(D)300
(E)450


30.  If n = pqr, where p, q, and r are three different positive prime numbers, how many different positive divisors does n have, including l and n?
(A)3
(B)5
(C)6
(D)7
(E)8

解答：
24、不是each off，应该是each of吧！就是问每一年哪一种毕业生的数量大约占每一年总数的1/4，很显然，总数大约是4000多一点（每一年差不多），因此占1/4的就是Bachelor's degree了
29、设seating capacity为x，那么多售了150张，就是售了x+150张，而分成两场来演出，每场2/3x，加起来就是4/3x
方程为x+150=4/3x，解得x=450
30、p,q,r为质数，他们任意组合都能构成n的约数（divisor），因此所有的约数为1,p,q,r,pq,pr,qr,n,一共8个
by xiaoyaozi

susuyaaUID: 2324593

(9510)
SECTION 5
The median of 10, 15, x, and y is 18.5, and x<y.
15. x     22
答案C,我选B?


21. For how many of the years shown after 1950 was there a decrease from the previous year in the number of registered cars?
(A) Nine
(B) Eight
(C) Seven
(D) Six
(E) Five

25. If the number of registered cars were to increase yearly through the year 2000 at the same average annual rate shown for the period 1981-1985, for which of the following years would the number of registered cars be closest to 76 million?
(A) 1995
(B) 1996
(C) 1997
(D) 1998
(E) 1999

解答：
15、median为中数，如果是奇数个数，那么中数就是从小排到大的最中间那个；如果是偶数个数，那么中数就是从小排到大的最中间两个数的平均数。而这题的中数为（15+X）/2=18.5，求得X=22
21、就是那条上面的曲线。后一年比前一年的车的数量少的情况有多少年，就是我用红圈标出来的地方，你数数，一共有8个
25、从81年到85年，你自己看看，每年增长3million，到85年时是40million，因此要达到76million，还需要36million，每年3million，要12年，就是85+12=97 选C
by xiaoyaozi

zyuan12UID: 2625480

问个跟数学有关的问题...
高分突破的第三篇是真题,第四篇是模拟题?

xiaoyaozi5566UID: 2510336

24# zyuan12
额，我没用过那书

jinziqiUID: 2387034

看大家发了好多图表题……是不是这是最难的最容易错的啊?
我还想问一题……模考第四辑的……
The average (arithmetic mean) of 50 measurements is 34.6, and the least and the greatest of the measurements are 18.3 and 50.9 respectively.
The median of the                                         34.6
50 measurements
median是中数,这个我已经了解了~呵呵
谢谢！

解答：
这种题果断选D，不能判定大小，50个数的平均数是34.6，从这一点得不出关于中间两个数的任何有用信息，中间两个数可以比34.6大，也可以小，也可以相等
by xiaoyaozi

susuyaaUID: 2324593

(9604) SECTION2  不好意思我问题有点多

12. (1/x)^2    x^2
答案A,我选D?

An identification code read fromleft to right consists of 2 digits, a dash, 3 digits, a dash, and then 4 digits.Each digit can be any number from 0 through 9.

14. The number of different identification codes possible               10^9
答案 C

29. An experiment has three possible outcomes, l, J, and K. The probabilities of the outcomes are 0.25, 0.35, and 0.40, respectively. If the experiment is to be performed twice and the successive outcomes are independent, what is the probability that K will not be an outcome either time?
(A) 0.36
(B) 0.40
(C) 0.60
(D) 0.64
(E) 0.80
答案 A


23. For a total of $1, 500 that is advanced in separate cash amounts,
for which of the following is the total of the transaction fees the LEAST?
(A) Two cash advances of $750
(B) Three cash advances of $500
(C) Six cash advances of $250
(D) Two cash advances, one of $1, 100 and one of $400
(E) Two cash advances, one of $1, 250 and one of $250

解答：
12、这个如果没有前提的话，答案显然是错的
14、一共9位，每位有0到9十种选择，因此组合数一共是10^9种不同的情况，因此为C，相等
29、每一次实验不出现K的概率为（1-0.4）=0.6，两次都不出现K的概率就为0.6*0.6=0.36
23、这个表是一个收费表，就是如果你要$1000的话就要1%的费用，$500的话就要2%的费用，因此E的费用最少（多谢xueyi版友的解答）
by xiaoyaozi

susuyaaUID: 2324593

(9604) SECTION5

9.
1 gallon = 8 pints
1 quart = 2 pints

The least number of half-pint bottles needed to hold x quarts of milk

The least number of one-quart bottles needed to hold x gallons of milk

Ans: C

  

15. The perimeter of the shaded region in the rectangle              2(根号2) + 2
Ans: D, 我选C??

20.(:PROBLEMSOLVE)The average (arithmetic mean) of ｜x｜and x equals
(A) x if x > 0, and equals 0 if x≤ 0
(B) -x if x < 0, and equals 0 if x ≥ 0
(C) 0, regardless of the value of x
(D) x, regardless of the value of x
(E) |x|, regardless of the value of x

解答：
9、左边，x quarts=2x pints，需要half-pint bottle 4x个才能装下；右边，x gallons=4x quarts，用one-quart bottle的话需要4x个才能装下
因此左右两边相等
15、我想题目没有交代上面那个点是中点吧？不过看图来看应该是中点，这个答案是官方的么？
不清楚!网上下的9604模考练习(三)word档里给的答案


20、这个...（｜x｜+x）/2的问题，好像A比较显然吧
by xiaoyaozi

by the way, 你是文科生么？
惭愧的理科= =+
有时候因为对题意不了解就不知道再问什么?
本人的数学确实有待加强...
看来我好像问题太多打扰到楼主了真是抱歉阿!!

susuyaaUID: 2324593

22. If health care expenditures accounted for 11 percent of the gross domestic product in 1989, then the gross domestic product was approximately how many billion dollars?
(A) 605
(B) 5, 000
(C) 5, 500
(D) 6, 050
(E) 6, 500

29. The sum of the first 50 positive integers is 1, 275. What is the sum of the integers from 51 to 100.
(A) 2, 525
(B) 2, 550
(C) 3, 250
(D) 3, 775
(E) 5, 050

~谢谢了!!
解答：
22、上面写了total 550 billions，占国内产值的11%，因此国内产值为550除以11%=5000 billions
29、在1275的基础上加50*50=2500就OK了，因为51比1大50，52比2大50...依次类推
by xiaoyaozi

zyp8756UID: 2594775

1.（40% of 50）+60                (60% of 50) + 60
答案给的是a应该是错了吧？
2.23（784）                        24（783）
这个答案是b 也不对吧

解答：
1、显然右边大
2、这个是乘法的话应该是右边大，解释请看楼下:)
by xiaoyaozi

xueyiUID: 2647060

30# zyp8756
第一题选B。
第二题选B。23*783+23<23*783+783