prep上的几道不会的题～～我相信很多TX也不会～大家来请大牛讲讲吧～～

王美美最美丽

Working alone at its own constant rate,a machine seals K cartons in 8 hours and working alone at its own constant rate,a second machine seals K cortons in 4 hours.If the two machines,each working at its own constant rate and for the same period of time,togher sedled a certain number of cartons what percent of the cartons were sealed by the machine working at the faster rate.



A 25%

B33又 3/1

C50%

D66 又3/2

Ｅ７５％





Bobby bought two shares of stock,which he sold for $96 each.If he had a profit of 20 percent on the sale of the other share then on the sale of both shares combined Bobby had.

A  a profit of $10

B  a profit of $8

C  loss of $8

D  loss of $10

E neither a profit nor a loss





Of the 800 employees of company X,70 percent have been with the company fir at least ten years.If y of these “long-term” members were to retire and no other employee changes were to occur, what value of y would reduce the percent of “long-term”employees in the company to 60 percent?

A 200

B160

C112

D80

E56





The symbol * represents one of the four anithmetic operations: adition subtraction,multiplcation,and division. Is (5*6)*2=5*(6*2)?

(1)    5*6=6*5

(2)    2*0=2

A 条件一就可以判断

B条件二就可以判断

C条件一和条件二联合才判断

D条件一，条件２分别都可以判断

E两个条件联合起来也不能判断



Which of following lists the number of points at which a circle can intersecta triangle

A 2 and 6 only

B 2,4 and 6 only

C1,2,3,4 and 6 only

D 1,2,3,4, amd 6 only

E 1,2,3,4,and 6 only

王美美最美丽

我怎么觉得prep里的题比机经里的还难呢？？？怎么办啊～～～～一点信心都没有，两回模考数学都是４９～～～～

吉木乃

LZ，第二题你可能少掉条件了哦~
原体是这样的：
Bobby bought two shares of stock, which he sold for $96 each. If he had a profit of 20 percent on the sale of one of the shares but a loss of 20 percent on the sale of the other share, then on the sale of both shares combined Bobby had
a) a profit of $10
b) a profit of $8
c) a loss of $8
d) a loss of $10
e) neither a profit nor a loss
设两个shares分别为x1，x2，则有
x1+x1/5 = 96 => x1 = 80
x1-x2/5 = 96 => x2 = 120
所以Bobby花了200买入，96*2=192卖出，得loss of $8

吉木乃

最后一道也是有一半答案有点小问题~补上：）
C) 1,2,3 and 6 only
D) 1,2,3,4 and 6 only
E) 1,2,3,4,5 and 6
这样就好做啦！+U(又飘过来给一个思维方法当参考)
1 - Triangle is out side the circle and tangential
2 - Circle divides one side of triangle in 3 parts. Intersects only one side at 2 points.
3 - Inscribed circle. All sides of triangle tangent to circle.
4 - Circle intersects only 2 sides of triangle, 2 points each side.
5 - Circle intersects 2 sides , at 2 points each, and is tangential to the third side.
6 - Circle intersects all 3 sides, each of them at 2 points.

ccdsryx

第一题题目我都没读懂。。。。。。。。。。

王美美最美丽

LZ，第二题你可能少掉条件了哦~
原体是这样的：
Bobby bought two shares of stock, which he sold for $96 each. If he had a profit of 20 percent on the sale of one of the shares but a loss of 20 percent on the sale of the other share, then on the sale of both shares combined Bobby had
a) a profit of $10
b) a profit of $8
c) a loss of $8
d) a loss of $10
e) neither a profit nor a loss
设两个shares分别为x1，x2，则有
x1+x1/5 = 96 => x1 = 80
x1-x2/5 = 96 => x2 = 120
所以Bobby花了200买入，96*2=192卖出，得loss of $8

-- by 会员 吉木乃 (2009/11/5 10:11:03)

哎呀～～～我懂啦～～真是谢谢～～

王美美最美丽

最后一道也是有一半答案有点小问题~补上：）
C) 1,2,3 and 6 only
D) 1,2,3,4 and 6 only
E) 1,2,3,4,5 and 6
这样就好做啦！+U(又飘过来给一个思维方法当参考)
1 - Triangle is out side the circle and tangential
2 - Circle divides one side of triangle in 3 parts. Intersects only one side at 2 points.
3 - Inscribed circle. All sides of triangle tangent to circle.
4 - Circle intersects only 2 sides of triangle, 2 points each side.
5 - Circle intersects 2 sides , at 2 points each, and is tangential to the third side.
6 - Circle intersects all 3 sides, each of them at 2 points.

-- by 会员 吉木乃 (2009/11/5 10:13:44)

这个～～牛牛能不能给我用中文翻译下这个题目，小的我才疏学浅～～　用中文讲讲呗～～～

francineivy

Working alone at its own constant rate,a machine seals K cartons in 8 hours and working alone at its own constant rate,a second machine seals K cortons in 4 hours.If the two machines,each working at its own constant rate and for the same period of time,togher sedled a certain number of cartons what percent of the cartons were sealed by the machine working at the faster rate.



A 25%

B33又 3/1

C50%

D66 又3/2

Ｅ７５％

如无意外是选D
不要拿笔 你意念一下
（1）8小时那个家伙比4小时那个家伙效率低
（2）慢家伙速度：快家伙速度=1：2
所以快家伙占2/3

ydtweety

最后一道也是有一半答案有点小问题~补上：）
C) 1,2,3 and 6 only
D) 1,2,3,4 and 6 only
E) 1,2,3,4,5 and 6
这样就好做啦！+U(又飘过来给一个思维方法当参考)
1 - Triangle is out side the circle and tangential
2 - Circle divides one side of triangle in 3 parts. Intersects only one side at 2 points.
3 - Inscribed circle. All sides of triangle tangent to circle.
4 - Circle intersects only 2 sides of triangle, 2 points each side.
5 - Circle intersects 2 sides , at 2 points each, and is tangential to the third side.
6 - Circle intersects all 3 sides, each of them at 2 points.

-- by 会员 吉木乃 (2009/11/5 10:13:44)

读了半天，不大懂诶~也麻烦给我讲讲吧~

sure6

您太强悍了》。。