301. X是10-20的一个数，问X是质数吗？
（1）X+1能被3整除
（2）X+2是质数
应该选C，因为X可以是11或17，都是质数
302. 一种什么东西（好像是鱼），各个种类的数量分别是4，5，x，y，z，11（中间三个数记不清了，但我是按升序排列的），一段时间后，原来最少的那种增加了3，最多的那种增加了2，其他增加了1，问现在的range。
答案：7。小心啊，4+3变成7，5+1只有6，最大的11+2=13，所以range是13-6=7，不要看成13-7了。
303。 ((360)^2)^3=?, 就是分解成质因子的N次方就好了.
304. m and n are the tens and unit difits of a number. a number is twice m*n, what is the m in terms of n?
305. how many number between 1-60 share are prime, excluding 2, 3 and 5?
306. 0.06 of 1/2?
307. (DS) is the median salary of 21 teachers less than the average:
1. the average salary is 445,200
2. the 12 of the leachers, each earn less than 21,000
308. (DS)Two concerts, x and y. what is y?
a inequality was given but cant remember what was the inequality
1. 20x+15y>320
2. X=3/4y
309. An Isoceles triangle has as sides 4 and 10, what is the perimetre?
1. 14
2. 18
3. 20
4. 24
5. 28
310. On a number line, 4 points, A, B, C and D, are separated by equal distance. A is -2^24 and B is -2^23, what is D?
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