我也問幾題PP數學？請大大幫忙

sparkchen

78.      6841-!-item-!-187;#058&005248

For each customer, a bakery charges p dollars for the first loaf of bread bought by the customer and charges q dollars for each additional loaf bought by the customer.  What is the value of p ?

 

(1)  A customer who buys 2 loaves is charged 10 percent less per loaf than a customer who buys a single loaf.

 (2)  A customer who buys 6 loaves of bread is charged 10 dollars.

答案是C，我的答案是B

64.      5320-!-item-!-187;#058&004563

Are at least 10 percent of the people in Country X who are 65 years old or older employed?

 

(1) In Country X, 11.3 percent of the population is 65 years old or older.

 (2) In Country X, of the population 65 years old or older, 20 percent of the men and 10 percent of the women are employed.

答案是B，為何不是C

77.      9031-!-item-!-187;#058&006222

At a dinner party, 5 people are to be seated around a circular table.  Two seating arrangements are considered different only when the positions of the people are different relative to each other.  What is the total number of different possible seating arrangements for the group?

 

(A) 5

(B) 10

(C) 24

(D) 32

(E) 120

答案C

chejw

第一道 一定要结合才可以得出答案

条件1 （p+q）/2=90%p

条件2   p+5q=10

第二道 可能是题目的理解问题吧

首先题目问Are at least 10 percent of the people in Country X who are 65 years old or older employed?

翻译： 在Country X 65岁以上的人中有百分之多少是工作的，注意是占65岁以上的人的百分比，不是总体人数

因此条件2 就可以知道答案，因为有65岁以上的人当中，男受聘的有20%，女的有10%，所以这部分人占65岁以上的一定大于10%

第三道 P4，4=4*3*2=24

yankevi

也算了一下楼主的题目，哎。。吃力啊～关于77题目，因为我排列组合也是很差的。。

这是圆桌问题，比如说有ABCDE这5个人坐圆桌，如果是一般的排列就是P5,5==120

但是圆桌的话，你坐我左边和你做我右边是一样的，把圆桌的位置旋转一下。。ABCDE,BCDEA,CDEAB,DEABC,EABCD是一样的。就是在计算120种的可能性中，我每个的都重复计算了4遍，那么X+4X=120,X=24就是无重复的排列了。

关于第一题，在美国买东西可以小数的，你不要把2认为了是整数了，就觉得能推出：）

sparkchen

感謝兩位大俠解題

小弟知了

感謝