tt-1-2,7,8,9,10,24,30

allen0018

谢谢大家，我今天做了tt-1有数学题不明白，真不明白

希望大家帮忙

Q2:

A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the roller coaster.  If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars?

 

A.        0

B.        1/9

C.        2/9

D.       1/3

E.        1

Answer: c

allen0018

Q3:

If x and y are positive, is 4x > 3y?

(1)     x > y - x

(2)     x/y < 1

e

像这样比较大小的，到底应该怎么做？？？

每次都稀里糊涂

每次都心惊胆颤

allen0018

Q9:

A gardener is going to plant 2 red rosebushes and 2 white rosebushes.  If the gardener is to select each of the bushes at random, one at a time, and plant them in a row, what is the probability that the 2 rosebushes in the middle of the row will be the red rosebushes?

 

A.      1/12

B.      1/6

C.      1/5

D.     1/3

E.      1/2   key:b

我选的是d

我怀疑这2个白花布一样？

我是c1-3;   答案 怎么来的？

allen0018

Q18:

 

x        x                 2 in          x                                                                                    x

 

 

 

 

 

 

 

 

 

 

                                        

                                    Note: Figure not drawn to scale.

 

The figure shows a square patio surrounded by a walkway of width x meters.  If the area of the walkway is 132 square meters and the width of the patio is 5 meters greater than the width of the walkway, what is the area of the patio, in square meters?

 

A.      56

B.      64

C.      68

D.     81

E.      100

这题说的是什么意思???

答案是b

我发布上图片，怎么办？

allen0018

Q24:

If w and c are integers, is w > 0?

(1)     w + c > 50

(2)     c > 48

                  

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

e

我想问大家不等式同向加减的知识点

yaoyao99

Please please separate your questions into individual posts and add a good title for each one (e.g. 涛涛 GWD-xx-yy）

Please also search for existing discussions before you post your questions:

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=176560&page=1

[原创]*GWD数学*讨论贴集锦！  by maki        点击此处查看
涵盖了涛涛31套将近一半的数学讨论

顾风

以下是引用allen0018在2006-7-10 23:38:00的发言：

谢谢大家，我今天做了tt-1有数学题不明白，真不明白

希望大家帮忙

Q2:

A certain roller coaster has 3 cars, and a passenger is equally likely to ride in any 1 of the 3 cars each time that passenger rides the roller coaster.  If a certain passenger is to ride the roller coaster 3 times, what is the probability that the passenger will ride in each of the 3 cars?

 

 

A.        0

B.        1/9

C.        2/9

D.       1/3

E.        1

Answer: c

c(1,3)*c(1,2)/3^3，即坐一1次，坐二一次，坐三一次相乘后除以三的三次方

顾风

以下是引用allen0018在2006-7-10 23:42:00的发言：

Q3:

If x and y are positive, is 4x > 3y?

(1)     x > y - x

(2)     x/y < 1

e

像这样比较大小的，到底应该怎么做？？？

每次都稀里糊涂

每次都心惊胆颤

条件1为 2x>y，即 4x>2y

条件2为 x,y同正或同负，如果同正，x<y,如果同负 x>y

所以得不出结论

顾风

以下是引用allen0018在2006-7-10 23:46:00的发言：

Q9:

A gardener is going to plant 2 red rosebushes and 2 white rosebushes.  If the gardener is to select each of the bushes at random, one at a time, and plant them in a row, what is the probability that the 2 rosebushes in the middle of the row will be the red rosebushes?

 

 

A.      1/12

B.      1/6

C.      1/5

D.     1/3

E.      1/2   key:b

我选的是d

我怀疑这2个白花布一样？

我是c1-3;   答案 怎么来的？

是这样做的，不要用组合

a,b,b,a; a,b,a,b; a,a,b,b;

b,a,a,b;b,a,b,a; b,b,a,a;所以是 b，understand?

顾风

以下是引用allen0018在2006-7-10 23:49:00的发言：

Q18:

 

 

                                        

                                    Note: Figure not drawn to scale.

 

 

The figure shows a square patio surrounded by a walkway of width x meters.  If the area of the walkway is 132 square meters and the width of the patio is 5 meters greater than the width of the walkway, what is the area of the patio, in square meters?

 

 

A.      56

B.      64

C.      68

D.     81

E.      100

这题说的是什么意思???

答案是b

我发布上图片，怎么办？

w = 5+x

s = (5+x+2x)*x+(5+x)*x*2+(5+x+2x)*x = 132

所以 42+48+42 = 132 , x=3

即sw =64