[问题]请教几道数学题

confuciousUID: 158812

1.[FONT=arial]MS.Smith got an 8 percent cost-of -living raise of $20 per week.
A  Ms. Smith's new weekly salary
B. $260[/FONT] [/SIZE]  
我是这么算的,20/8%=250,所以选了个B,可是没想到答案是A.这是为什么?

2.A: 12+3
B: (4/7)*7
我选A,可是答案是C.我彻底昏死过去.......

3.2AF=AB=BD=DE=AE
A: The sum of the area of triangular region ABF and the area of triangular region CDE
B: The area of rectangular region BCDE
这道题困惑就在与没有给图,我都不知道该怎么画

4. A: The least positive integer that is divisible by both 14 and 21
B: The least positive integer that is divisible by both 14 and 28
我觉得是42和56,所以选B,结果答案是A.难道是我题目理解错了?

5.P,Q,R,S, and T are consecutive positive integers in that order.
A: (P+T)/2
B: R
这道题我是真的不知道该怎么弄它,答案是C

6.In a certain group of people, 3/4 of the people are men and 1/2 of the people have brown eyes.
A: Fraction of people in the group who are men who do not have brown eyes
B:1/4
我认为是3/4*1/2=3/8, 所以我选A.但是答案是D.为什么呢?

guoya_2008UID: 139505

1,设 s原工资为x,则0.08x=20，因此x=240
  所以新的工资为：240+20=260，故选a
2,我估计是12+3中间的+号应为除号。
3，我不会在留言板画图，你找同学问吧。
4，第一个为42，但是第二个为28，因为28本身能被自己整除。
5，p=r-2, t=r+2, 因此（p+t）/2=r
6, 约束不够，因为1/2 of the people have brown eyes 不等于说1/2 of the men have brown eyes.

confuciousUID: 158812

哦,明白了，多谢!

confuciousUID: 158812

1. A sealed rectangular tank, which has inside dimendions of 30 by 40 by 50 centimeters, is particular full of water.
A: The depth of the water when the tank is level and rests on  one of its 30-by 50- centimeter faces
B: The depth of the water when the tank is level and rests on one of its 30-by 40-centimeter faces.
这题吧,第一句话看懂了，可是A,B选项就没看懂,不知道它想问什么,郁闷.

2.After 2 femals leave a party, there are twice as many males as females. Then 9 males leave and there are twice as many females as males.
A: the total number of people left at the party after the 9 males leave.
B: 8
这题也是没看懂题. there are twice as many males as females,到底男的是女的2倍还是女的是男的2倍,不明白

confuciousUID: 158812

3.John has a flat square garden with a perimeter of x feet. David has a flat rectangular garden with a perimeter of x feet and the length 1 foot longer than the width.
A: The area of John's garden
B: The area of David's garden
我认为the area of John's garden is (x/4)的平方, 而David's garden 两条边是,(x-2)/4, (x+2)/4.所以面积就是(x-2)(x+2)/16. 这两个没法比,所以我选D,结果答案是A.

4.At noon today, Ann, Betty, Cathy, and Dot had exactly $1 apiece. Then during the next minutes, Ann gave $1 to Betty who gave $2 to Cathy who gave $3 to Dot. None of them gave or received any other money.
A: The amount of money Betty had left at five minutes past noon today
B: The amount of money Cathy had left at five minutes past noon today
我想两个人都没钱了，但是这个5分钟放这里什么意思?难道换一个1分钟答案就不一样了?"nest minutes"什么意思呢?

5.d>0
A: The total interest earned on d dollars invested for 3 months at 11 percent simple annual interest
B: (11/3)*(d/100) dollars
我觉得应该是0.11d开4次方,比B大，所以选A.不过答案是B.

sinomanUID: 163557

1.B，两种情况的深度比较，就是长、宽、高相互调换一下。
2.D，用6和9代入第二个约束条件试算即可，there are twice as many males as females意思是男人数目是女人的2倍。
3.(x/4)(x/4)与(x+2)/4*(x-2)/4比较，x*x/16与(x*x/16)-1/4,前者大。
4.都没有钱了。可能应是next five minutes,再说next minutes好像没有这种说法。
5.d*0.11*(3/12)=d*(0.11/4),B项是d*（0.11/3),选B没错。 :p

sinomanUID: 163557

第二题有误，应为：
f-2=m/2;
m-9=f/2
（f代表女，m代表男）
解方程的：f＝26/3,m=40/3;
可见选A。
（好像题目有错，人不可能不是整数） :D  :D  :