请教各位牛牛，给我个思路，谢谢 

1.At least 100 students at a certain high school study Japanese. If 4 percent of the students at the school who study French also study Japanese, do more students at the school study French than Japanese?

(1)  16 students at the school study both French and Japanese.

(2)  10 percent of the students at the school who study Japanese also study French.

answer:B

2.In the xy-plane, does the line with equation y = 3x + 2 contain the point (r, s) ?

(1)  (3r + 2 - s)(4r + 9 - s) = 0

(2)  (4r - 6 - s)(3r + 2 - s) = 0

answer:C

3.A vending machine is designed to dispense 8 ounces of coffee into a cup.  After a test that recorded the number of ounces of coffee in each of 1,000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data.  If the 1,000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12 listed amounts are within 1.5 standard deviations of the mean?   (A) Four  (B) Six  (C) Nine  (D) Ten (E) Eleven

answer:E

(A) 100% decrease  (B) 50% decrease  (C) 40% decrease  (D) 40% increase  (E) 50% increase

answer

5.If n is a positive integer and n² is devisible by 72 then the largest positive integer that must divide n is=?

answer:12

刚做完几道，先说说做过的：

2、我是简单带入：

(1)  (3r + 2 - s)(4r + 9 - s) = 0

直接计算3r+2=s or 4r+9=s  注意原文由y=3x+2

(2)  (4r - 6 - s)(3r + 2 - s) = 0

也一样：4r-6=s  or 3r+2=s 

因为是or，所以都不唯一确定，但是同时考虑下，就OK。

4，看懂题目，是说和平方成正比，所以反比的增加了100%，就是分母增加了2倍，那么正比的就是分子也要同样增加2倍。所以是开根号：根号2=1.41....  所以最接近的就是0.4

谢谢.

有没有大牛解释一下剩下的题嘞...

1>

１＞１６人同时学习法语和日语
只能推出 学法语的有４００人
而学日语的有可能是２００或５００，大于１００就行
２＞１０PERCENT学日语的人和４PERCENT学法语的人数是一个值
THUS，学法语的人多

7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1,000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data. If the 1,000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce,howmany of the 12 listed amounts are written 1.5 standard deviations of the mean?

four
six
nine
ten
eleven

你的题目少了数据

题目问在这１２个数中几个数是在１。５倍的DEVIATION FROM MEAN

０。３＊１。５＝０。４５

１２个数中１１个都属于（８。１－０。４５）到（８。１＋０。４５）的这个区间

答案：E

4>

Rate = = k Square(A) / B, where k is a constant.

Now if the concentration of B is increased by 100%, it means B becomes 2B.

So new rate = k Square(A)/2B
in order to keep the same rate A should be INCREASED to SQrt(2) times A.

Square Root of 2 is approximately 1.414. So the new concentration of A is 1.41A which is approximately 40% increase in A.

N的平方＝K＊７２＝K＊３＊３＊２＊２＊２
因为N是整数，所以K的最小值是２，THUS N的最小值是１２

所以１２是最大的能除尽N的

可能我没说清。。。自己理解下