求助最新13套试题第六套中的一些数学题

海仪

求助最新13套试题第六套题的一下题目的解法思路：

Q11:

A certain business produced x rakes each month form November through February and shipped x/2 rakes at the beginning of each month from March through October.  The business paid no storage costs for the rakes from November through February, but it paid storage costs of $0.10 per rake each month from March through October for the rakes that had not been shipped.  In terms of x, what was the total storage cost, in dollars, that the business paid for the rakes for the 12 months form November through October?
                     A C

 

A.     0.40x

B.     1.20x

C.     1.40x

D.     1.60x

E.      3.20x

Q23:

 

O

 

 ●

             

                        B●           ●C

 

 

 

 
                            

O      ●

 

                      

                        A●          ●D

O是圆心，BC是过圆心的直径，ABCD十个矩形

 

In the figure shown, what is the area of the circular region with center O and diameter BC? E C

(1)     BC/AB = 3/4

(2)     BD = 25

Q28:

Last Sunday a certain store sold copies of Newspaper A for $1.00 each and copies of Newspaper B for $1.25 each, and the store sold no other newspapers that day.  If r percent of the store’s revenues from newspaper sales was from Newspaper A and if p percent of the newspapers that the store sold were copies of newspaper A, which of the following expresses r in terms of p?

C D

A.     100p / (125 – p)

B.     150p / (250 – p)

C.     300p / (375 – p)

D.     400p / (500 – p)

E.      500p / (625 – p)

Q33:

Enrollment in City
                                    College in 1980 was 83⅓ percent of enrollment in 1990.  What was the percent increase in the college’s enrollment from 1980 to 1990? B C

 

A.     10%

B.     16⅔%

C.     20%

D.     25%

E.      183⅓%

Q37:

Of the families in City X in 1994, 40 percent owned a personal computer.  The number of families in City X owning a computer in 1998 was 30 percent greater than it was in 1994, and the total number of families in City X was 4 percent greater in 1998 than it was in 1994.  What percent of the families in City X owned a personal computer in 1998? E A

 

A.     50%

B.     52%

C.     56%

D.     70%

E.      74%

在此先谢过！

海仪

还有一道题，我觉得答案似乎有问题，还是我考虑的不对？还希望高人指教

Q6:

The ratio of the number of red cars in a certain parking lot to the number of black cars is 3 to 8.  If there are 72 black cars in the lot, how many red cars are there in the lot?  D C

 

A.     11

B.     15

C.     24

D.     27

E.      32

Elynn_Chen

q11

楼主可以把从3月到10月（只考虑这8个月因为前四个月不收费）这个看成一个数列d＝－1/2，三月份的数量为a1

因为月初运出，所以a1＝3.5 a8＝0 a1到a8的和为 (3.5+0)*8/2=14 (这就是应该交银子的数量总和）

所以应该选1.4

ps:下一题的图没有太看明白

[此贴子已经被作者于2007-5-4 22:31:30编辑过]

Elynn_Chen

 

Q28:

(1.00*p%)/[1.00*p%+1.25*(1-p%)]=r%

求出来就行了

Elynn_Chen

Q33: 根据条件1980为83⅓ 1990为1

增长：（1－83⅓）/83⅓ =1/5  (问题问得增长是以1980为基数的） 

Elynn_Chen

Q37: [40％×（1＋30％）]/[1+4%]=50%

Q6: 貌似应该选24。。。

[此贴子已经被作者于2007-5-4 22:51:09编辑过]

海仪

谢谢ELYNN的做答

eng70778

以下是引用Elynn_Chen在2007-5-4 22:50:00的发言：

Q37: [40％×（1＋30％）]/[1+4%]=50%

Q6: 貌似应该选24。。。

    

Q6为啥是24？？

mimixiaxia

我也不明白为什么是24

mimixiaxia

23：

设BC=3X，则AB=4X，(3X)^2+(4X)^2=(25)^2,就可以求解了啊