Rober之家12月数学机经总结[附解题思路][注意]

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Robert之家数学机经总结[附解题思路](2003.12) 本机经总结最后更新于 2003年12月18日09:20,目前共有17道题 本数学机经总结由Robert之家辅导中心制作完成,欢迎加入数学总结组,mailto: robert@topway.org 本站原创,未经授权，严禁传统媒体转载，网络转载请注明来源 http://www.topway.org 【注意】 1.[参考答案]表示JJ总结小组自己的答案 2.[思路]表示JJ总结小组自己的做题思路 3.[注]表示JJ总结小组或原始作者指出需要注意的地方 4.[讨论]表示题目不全或JJ总结小组不确定，请大家讨论 5.编号说明:前四位表示机经所在月份.后三位表示机经编号. 6.[来源]表示本题机经的原始机经所在. ----------------------------------------------------------------------------------------------- 0312001,有一道题较怪，说能否确定N?， 条件是 (1) (69+N)^1/2，(94+N)^1/2 是连续整数 (2) (94+N)^1/2，(121+N)^1/2 是连续整数 [参考答案]d [思路]69+n，94加n,121+n分别为144，169，196，条件1和2皆可得到n是75 [来源] 潜水代表首次发言-一点机经 0312002,两条平行线，一条有5个点，一条4个点问能组成多少个直角三角形 [参考答案]70 [思路]C(5,2)*4+C(4,2)*5 [来源] 潜水代表首次发言-一点机经 0312003,X is a positive integer. 2-height of X is defined as the greatest negative integer n where 2^n is a factor of X. K and M are two positive integers. Whether 2-height of K is greater than 2-height of M? a. K is greater than M b. K is even times of M [参考答案]b [思路]上月G经 [来源] 小红熊历险记--阳光总在风雨后 （机经篇 0312004,X, Y and Z are three different prime numbers. How many factors does X*Y*Z have?[参考答案]8 [思路] [来源] 小红熊历险记--阳光总在风雨后 （机经篇 0312005,XY>Z? a. XYZ>1 b. XYZ^2=1 [参考答案]c [思路]由1，2得到z<1,在由1，得到xy>1 [来源] 小红熊历险记--阳光总在风雨后 （机经篇 0312006,XYZ>0? a. XY>0 b. YZ>0 [参考答案]e [思路]xy>0.z可正可负，确定不了 [来源] 小红熊历险记--阳光总在风雨后 （机经篇 00312007，7^3*7^4=? [参考答案]7^7 [思路]原式即为7^(3+4) [来源] 小红熊历险记--阳光总在风雨后 （机经篇 00312008,A is 25% less than B and B is 25% less than C. How much percent is A less than C? [参考答案]1/3 [思路]1*(1-0.25)*(1-0.25)=9/16=1-7/16 [来源] 小红熊历险记--阳光总在风雨后 （机经篇 00312009,A can finish one job in X hours. A does this job three times as fast as B does. If A and B work together, how many hours can they finish the job [参考答案]3/4x [思路]1/(1/x+1/3x) [来源] 小红熊历险记--阳光总在风雨后 （机经篇 0312010,一公司A业务占总收入的25%，B业务占t%,C业务占余下的，B业务收入是150，000 C业务是总收入-225，000 求t=? [参考答案]50 [思路]150000/(T%)-225=150000/T%* [来源] JJ 0312011，If X is between 4497 and 4509, which number is closest to 23/(30X)? [参考答案]3451 [思路] [来源] JJ 0312012，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.) [参考答案]7BAGS [思路] [来源] JJ 0312013,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 [参考答案]8 [思路]2/(1-1/4) [来源] JJ 0312014,1998 sales increases x percent from 1997, 1999 sales decreases x percent from 1998, 1999 is 9 percent less than 1997. What is X? [参考答案]30 [思路](1+X)*(1-X)=0.09 [来源] JJ 0312015,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 [参考答案] [思路]见上月G经 [来源] JJ 0312016，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 [参考答案]E [思路]不知道是几个数，判断不了 [来源] JJ 0312017， 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? [参考答案] [思路]84*0.5*（4/7） [来源] JJ

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