21. 在电话厅前排队，J前有13个人，问队伍总共多少人
（1） C后有16个人
（2） C前J后有3个人
My Answer: C

22. A circle inscribed in an equilateral triangle with side length = 10. What is the area of inscribed circle?

23. 机经的题目，W到X到Y到Z，三个送信人，一个速度70mile/分钟，一个速度80mile/分钟，一个速度100mile/分钟，总长750mile 求X到Y长，
答案是240

24. x = (10 的100 次方), if (x的x次方) = (10 的k 次方), what is k?
My Answer: k = 200. (Not sure if my answer is correct)
Old JJ:
X=10^100，有X^X= 10^K， 问K等于多少
remeo评价意见：10^102

25. If X is between 4497 and 4509, which number is closest to 23/(30X)?
My Answer: 3451

26. A right triangle is on top of a square. Square side is 100, right triangle sides are 60, 80 and 100 (common side with the square). How many bags of fertilizer to cover entire area? (1 bag covers 2000 sq. feet.)
My Answer: 7 bags.

27. Make a code of different letters from 10 letters (A,B, ….). What’s the ratio of 5 letter code to 4 letter code?
My Answer: P(5, 10)/P(4, 10) = 6

28. r+s+t 是偶数么？
(1)r+s是偶数
(2)s+t是偶数

29. 有线段AC，AC上的一段AB正好是某圆柱体的体对角线(有图，看图会很清楚，我的描述可能不大清楚)，能求出AC的长么？
(1)BC=2
(2)AC有3/4长度在圆柱体内

30. 1998 sales increases x percent from 1997, 1999 sales decreases x percent from 1998, 1999 is 9 percent less than 1997. What is X?
My Answer: 30 percent

31. R=S(100)/P, in the equation, R is the real salary of a person, S is the current salary, and P is a kind of index. Whether the person K's real salary now is more than the real salary of 1967? (1)K's current salary now is 94% more than that of 1967
(2) the index of 1967 is 100 and the index of now is 182

32. a, b are nonnegative numbers and (a-b)/(a+b)=1/2, which one of the following must be true?
作者答案及思路：(Choice C: a>b)

33. A和B两个工程，A占2/3，B占余下的，B要花的时间是7/5 as much as A 问B花的时间占总共时间多少，
我的答案好象是7/17

34. y=1/(3-6/(x-4)), What is x defined as?
I 4
II 6
III 8

35. 有一个连续数的集合，问7是否在这个集合里面
a) -7在里面
b) 9在里面

36. A rectangle ABCD area is 84, point E is on line AB and AE/EB = 4/3, point F is on line DC, what is area of triangle AFE?

37.一个圆圆心在（0,0），一直线y=x，k同时在圆上和线上，问k坐标：
答案：（跟号2 除以1，跟号2 除以1）

38.JJ本月题99到301间的偶数的和
答案：20200
方法：99到301间的偶数的和=100到300间的偶数的和，等差数列求和=(A1+An)*N/2=(100+300) * 101/2=20200

39.JJ本月题 (X^ N) / （X-1）= X ^ (N-1) + X ^ (N-2) + …+1, 且7^8= 一个具体的数值C，问7^9=?
答案：
方法：假设X=7, N=9, 那么7^9 / 6 = 7^8 + 7^7+7^6+…+1
假设X=7, N=8, 那么7^8 / 6 = 7^7+7^6+…+1
因为 7^8=C，所以 7^7+7^6+…+1 = C/6
综合以上=〉 7^9 = 6（C+C/6）=7C/6
说明：具体公式可能略有偏差，但方法是这样的，请大家掌握此类方法，勿记答案。

40.ABCDEFG中随便取3个，但是AB不能在一起，问可能性？
答案：C(7,3)-5