几道数学机经不会，求问~~

几道数学机经不会，求问~~

1 In
the store of a car dealer, less than 10 cars are equiped with fog light, and
40% of the cars have  **window, Is the
dealer has more car with fog light than those with **window?

(1) 80%的车有雾灯但是没有windows T

(2)52 cars have fog light or window or both

2、
    

. 1到12连续12个正整数，放到如下的4×3的方格里，问X等于几，空白的地方我用B表示，要求每一个上下左右（vertical or horizontal)的格子里有相邻的数（10的位置也可能是第二个，实在记不清楚了），选项有2，5，8，11，12

3、有一个表格，10 rows and 10
columns, 每个9‘s 的第N row 都是以N-I表示，N从1到10。问这个表格所有数的均值。

我画不出来…就是那个“9‘s 的第N row”是个啥东西..

4
    

一个公司里男生有undergraduate
学历的比例为1/4，女生有undergraduate学历比例为2/5，全公司有undergraduate比例为1/10，问全公司女性比例为多少

0.5a+0.4b=0.1(a+b)可以算出来ab之间的关系，然后用b/(a+b)就好

 这个求出来为什么是负数啊~~

1 In the store of a car dealer, less than 10 cars are equiped with fog light, and 40% of the cars have  **window, Is the dealer has more car with fog light than those with **window?

(1)
                80%的车有雾灯但是没有windows 
                (2)52 cars have fog light or window or both

解答：

设总车辆X个，window的车0.4X.有雾灯的Y个，Y<10.求0.4X-Y<0?

(1)0.8Y 无window——既有雾灯又有window的是0.2Y

(2) 52=0.4X+Y-既有雾灯又有window的数量

（1）+（2）0.4X+0.8Y=52——0.8Y<10——0.4X>44——0.4X-Y>0

答案C.

1 In the store of a car dealer, less than 10 cars are equiped with fog light, and 40% of the cars have  **window, Is the dealer has more car with fog light than those with **window?

(1)
                80%的车有雾灯但是没有windows 
                (2)52 cars have fog light or window or both

更正解答：

设总车辆X个，window的车0.4X.有雾灯的Y个，Y<10.求0.4X-Y<0?

(1)0.8Y 无window——既有雾灯又有window的是0.2Y

(2) 52=0.4X+Y-既有雾灯又有window的数量

0.4X=52-Y+(既有雾灯又有window的数量），0.4X的最小值，是让既有雾灯又有window的数量为0，及0.4X>42>10>Y,所以D本身是一个充分条件。

答案B.