9. 图书馆里有2100还是21000本书。条件和问题记不清了不要过于指望,看方法!好像是说英语写的有50%,十年前的45%,英语十年前的有25%,问的是近十年非英语写的有多少本还是神马?LZ只记得自己画了个图,比例大家看见了自己往里面算吧,不难。
参考答案:待定
思路:
LZ图很给力,这种2×2条件的,图出来,做错都难。
参考prep的一道题吧,绝非原题,参考解题思路。
2. 142-!-item-!-187;#058&000140
Of the students who eat in a certain cafeteria, each student either likes or dislikes lima beans and each student either likes or dislikes brussels sprouts. Of these students, dislike lima beans; and of those who dislike lima beans, also dislike brussels sprouts. How many of the students like brussels sprouts but dislike lima beans?
(1) 120 students eat in the cafeteria.
(2) 40 of the students like lima beans.
【答案】D
【思路】
beans ~ beans
sprouts a b
~ sprouts c d
t
The table above shows the amount of waste material, in tons, recycled by each of five counties in a single year and the amount of waste material, also in tons, that was disposed of in landfills by the five counties in that year. Which county had the lowest ratio of waste material disposed of to waste material recycled in the year reported in the table?
a) A
b) B
c) C
d) D
e) E
答案:C
20. 有一个圆心在原点,半径为5的圆,然后问下面那些直线能和这个圆相交
I y=2x+1
II y=2(x-1)……………………(大概是这种形式)
III y=?x-6
选项分别是only I、 only II、 only III、 only I and II、 3个都是
参考答案:E
思路:
将x=0和y=0分别代入,得两个点,看是否在圆内;
y=2x+1=》(0,1),(-1/2,0)
y=2(x-1)=》(0,-2),(1,0)
y=x-6=》(0,-6),(6,0)此时需要计算三角形的高和半径大小关系:6×6=6*2^1/2*h=>h=6/(2^1/2)=6/1.414=4.24<5
25: A产品卖了3 times as much as B, A 的profit是A 成本的80%,B 的profit 是B成本的20%,问profit占total 成本的多少
参考答案:待定
思路:
设A买了x件,profit为pa,cost为ca;B买了x/3,profit为pb,cost为cb;
根据题意,得
pa=ca×80%
pb=cb×20%
(pa×x+pb×x/3)/(ca×x+cb×x/3)=(3pa+pb)/(3ca+cb)=(24ca+2cb)/(3ca+cb)
缺条件
26. 再补个DS X+Y=53, X是一个数的平方,问Y是不是一个square. (1) 25<=x<=49, (2) Y is odd
参考答案:C
思路:
貌似应该说一下x,y为整数,小于53的平方数为:1,4,9,16,25,36,49;就是组合这几个数为53
(1)25<=x<=49;x=25=》y=28;x=36=》y=17;x=49=》y=4(平方数);不确定;
(2)Y is odd=》x为偶数=》x=4,16,36;y分别为49(平方数),37,17;不确定;
(1)+(2)=》x=36=》y=17;确定
30. x=a^2,问x的positive factor 个数
I odd II even III质数个,我选的I,当时证明的,不知道对不对。
参考答案:I
思路:
I odd=》4(1,2,4);9(1,3,9);16(1,2,4,8,16)
II even=》略
III质数个=》100(1,2,4,5,10,20,25,50,100)作者: levils 时间: 2010-11-26 17:28
31. 一道DS,冰激凌店卖三种冰激凌x,y,z,已知某天卖出的x与y的比例是9:2,问这一天一共卖了多少冰激凌
A. y:z=7:20
B. 一共卖的不超过120个.
应该选C,符合条件的,且小于120的数只有一组
参考答案:C
思路:
(1) y:z=7:20=>x:y:z=63:14:40;但是算不出具体数字;不确定;
(2) 不超过120个,只要满x与y的比例是9:2,可以例举出一堆来,如(9,2,1)
(1)+(2):根据比例可得,只能为(63,14,40)
34. 又想起一道DS,正方形A内切于圆B,圆B又内切于正方形C(一个套一个),问圆B的面积是否大于某一个数(数忘了)(即是否有最小值)
A. 知道A的边长最大为多少(有给定数字)
B. 知道C的边长最小为多少(有给定数字)
我选的是是A不行B行(这道题记忆有点混乱了,看看有没有人记得更清楚一些。)
参考答案:待考古
思路:
设A的边长为x;B的面积为π(x/2)^2 ; C的半径=x/(2^1/2)
知道三者关系,就是通过A or C得到B,然后比较大小。
36. 有一题是127员工mean平均工资350,000,以下哪种说法对?
1。有至少64人的平均工资多于或等于350,000
2。至少有64人的工资少于350,000
3。。。。
A1
B2
C3
D1,2
E123
我选A
参考答案:A
思路:
参考PREP,绝非原题,参考思路,练习
Last month 15 homes were sold in Town X. The arithmetic mean sale price of the homes is $150,000 and the median price was $130,000. Which of the following statements must be true?
I. At least one of the homes was sold for more than $165,000
II. At least one of the homes was sold for more than $130,000 and less than $150,000
III. At least oe of the homes was sold for less than $130,000.
Answer choices
I only
II only
III only
I and II
I and III
43. m^2+n^2=40,m^3+n^3=?
参考答案:224
思路:
权当m,n是整数吧,小于40的平方数(1,4,9,16,25,36)
m=2 or 6 ; n=6 or 2
44. 下面哪个不是多面性的对角线 A 5,B 6,C 7,D 9,E 20 (整理者注:我觉得狗主人要表达的是多边形,我在跟狗主人确认中。)
参考答案:待考古
45. 连续2次打折 a reduced price is same as if the price is reduced by 70%. 问,第二次打折多少
条件不记得了,好像给了第一次打折多少?(这题我没明白什么意思)
参考答案:待考古作者: levils 时间: 2010-11-26 17:29
46. Rockets的比分比Eagles的比分在half of the game落后20分(貌似是这个数字),问最后谁赢了
(1)Rockets比Ealges比分多在the second half of the game.(不明白这句什么意思,the second half of the game是比赛结束嘛?还是指第三节比赛)
(2)好像是说Rockets的比分比Ealges的2倍
参考答案:待考古