美国数学大联盟杯赛五年级试卷精编版

美国数学大联盟杯赛五年级试卷精编版
美国数学大联盟杯赛五年级试卷精编版

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2015-2016年度美国“数学大联盟杯赛”(中国赛区)初赛

(五年级)

(初赛时间:2015年11月14日,考试时间90分钟,总分200分)

学生诚信协议:考试期间,我确定没有就所涉及的问题或结论,与任何人、用任何方式交流或讨论, 我确定以下的答案均为我个人独立完成的成果,否则愿接受本次成绩无效的处罚。

如果您同意遵守以上协议请在装订线内签名

选择题:每小题5分,答对加5分,答错不扣分,共200分,答案请填涂在答题卡上。

1. A 6 by 6 square has the same area as a 4 by ? rectangle.

A) 3 B) 6 C) 8 D) 9 2. Every prime has exactly ? positive divisors.

A) 1

B) 2

C) 3

D) 4 or more

3. If I answered 34 out of 40 questions on my math test correctly, I answered ? % of the questions correctly.

A) 75

B) 80 C) 85 D) 90

4. 120 ÷ 3 ÷ 4 × 12 =

A) 1 B) 10 C) 12 D) 120 5. 10 × 20 × 30 × 40 = 24 × ?

A) 1000

B) 10 000

C) 100 000

D) 1000 000

6. One of my boxes contains 1 pencil and the others each contain 5 pencils. If there are 101 pencils in my boxes, how many boxes do I have?

A) 19

B) 20

C) 21

D) 22

7. An electrical company imports 2016 light bulbs. Unfortunately, 25% of those are damaged. How many light bulbs are not damaged?

A) 25

B) 504 C) 1512 D) 2016 8. 50 × (16 + 24

) is the square of

A) -40 B) -4 C) 4 D) 80 9. Which of the following numbers has exactly 3 positive divisors?

A) 49

B) 56

C) 69

D) 100

10. Ten people stand in a line. Counting from the left, Jerry stands at the 5th position. Counting from the right, which position is he at?

A) 4 B) 5

C) 6

D) 7

11. On a teamwork project, Jack contributed 2/7 of the total amount of work, Jill contributed 1/4 of the work, Pat contributed 1/5 of the work, and Matt contributed the rest. Who contributed the most toward this project?

A) Jack B) Jill C) Pat D) Matt 12. Which of the following numbers is a factor of 2016? A) 5 B) 11 C) 48 D) 99 13. 2 × 4 × 8 × 16 × 32 × 64 =

A) 210

B) 215

C) 221

D) 2120

14. On a game show, Al won four times as much as Bob, and Bob won four times as much as Cy. If Al won $1536, how much did Al, Bob, and Cy win together?

A) $96 B) $384 C) $1920 D) $2016 15. The sum of two composites cannot be

A) odd B) even C) 11 D) 17

16. If a and b are positive integers such that a /b = 5/7, then a + b is

A) 12 B) 24 C) 36 D) not able to be determined 17. What is the greatest odd factor of the number of hours in all the days of the year 2015? A) 3

B) 365 C) 1095 D) 3285 18. If the current month is February, what month will it be 1 199 999 months from now?

A) January

B) February

C) March

D) April

19. Two angles are complementary. One of these angles is 36° less than the other. What is the measure of the larger angle?

A) 36° B) 54° C) 63° D) 72° 20. (The square root of 16) + (the cube root of 64) + (the 4th root of 256) = A) 12 B) 24 C) 32 D) 64 21. In ?ABC , m ∠A – m ∠B = m ∠B – m ∠C . What is the degree measure of ∠B ?

A) 30

B) 60

C) 90

D) 120

22. For every 3 math books I bought, I bought 2 biology books. I bought 55 books in all. How many of those are math books?

A) 11

B) 22

C) 33

D) 44

23. John wrote a number whose digits consists entirely of 1s. This number was a composite number. His number could contain exactly ? 1s.

A) 17

B) 19

C) 29

D) 32

24. Weird Town uses three types of currencies: Cons, Flegs, and Sels. If 3 Sels = 9 Cons and 2 Cons = 4 Flegs, then 5 Sels = ? Flegs.

A) 12

B) 24

C) 30

D) 36

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25. If the length of a rectangular prism with volume V is doubled while the width and the height are halved, the volume of the new prism will be

A) 4V

B) V /2

C) V

D) 2V

26. Rick and Roy each stands at different ends of a straight road that is 64 m long. They run toward each other. Rick ’s speed is 3 m/s and Roy ’s speed is 5 m/s. They will meet in ? seconds.

A) 1

B) 2

C) 4

D) 8

27. If the area of a certain circle is 2016, its radius is

A) sqrt(2016/π) B) sqrt(4032/π) C) 2016/π

D) 1008/π

28. In a toy shop, the cost of a Teddy Bear is 200% as much as that of a toy train. The cost of a toy train is 6/5 the cost of a pack of the wooden blocks. The cost of a pack of wooden blocks is $50. What is the cost, in dollars, of the Teddy Bear?

A) 60

B) 100

C) 120

D) 200

29. In the sequence 2016, 225, 141, 66, 432, 99, 1458 …, each term after the first term is the sum of the cubes of the digits of the previous term. What is the 100th term of this sequence?

A) 153 B) 351 C) 370 D) 371 30. What is the sum of all the positive divisors of 210?

A) 210 – 1

B) 211 – 1

C) 212 – 1

D) 213 – 1

31. It takes 4 hours for Mike and Lucy to finish a task. It takes Lucy and Jerry 5 hours to

finish the same task. And it takes 6 hours for Mike and Jerry to finish the same task. Lucy and Jerry first work on the task for 1 hour and 45 minutes. Then Mike takes over the task on his own. How many more hours does it take for Mike to finish the task?

A) 3

B) 4

C) 5

D) 6

32. If you sell a cloth at its current price, you get $40 profit. The total profit you get selling 10 clothes at 70% of its current price is equal to the total profit you get selling 20 clothes at $82 per cloth. What is the current price of a cloth?

A) 80

B) 100

C) 120

D) 125

33. There are 6 identical squares in the figure on the right. The side length of each square is 1. Of all the triangles constructed by connecting three of the 18 vertices in the figure, how many of them are triangles whose area is 2 and which has at least one vertical or horizontal side?

A) 12

B) 16

C) 24

D) 28

34. Pick up N numbers from 1 to 2015 inclusively, such that the sum of any three of the N numbers is divisible by 24. What is the maximum value of N ?

A) 83

B) 84

C) 168

D) 252

35. 汤姆有一件花了64美金买来的衬衫,他打算以比原价高出25%的价格出售,他会卖出多少钱?

A) $16

B) $32

C) $48

D) $80

36. 满足以下条件的最小整数是多少:“除以3余2,除以5余4,除以7余6。” A) 59 B) 61 C) 104 D) 106 37. 飞人以每小时360千米的速度飞行,这相当于每秒多少米?

A) 10 B) 36 C) 64 D) 100

38. 设A 为一个可整除11但不可整除10的正整数,若B 为一个颠倒A 数位的整数,那么B 必须被几整除?

A) 11 B) 22

C) 33

D) A, B, C 都不选

39. 珍妮花50美金买了一条围巾。她一开始准备以60美金卖出,然后把价格增加25%,再把新的价格减少20%并且出售。在这笔交易之中,她 ? 。

A) 赚了7美金 B) 赚了10美金 C) 亏了7美金

D) 亏了10美金

40. A , B

两个袋子里分别有若干个球,A 袋球和B 袋球的数量比是4:1。从A 袋中取出若干个球放入B 袋后,A 袋球和B 袋球的数量之比变为8:3;再从B 袋中取出若干个球放入A 袋后,A 袋球和B 袋球的数量之比变为9:2。两个袋子里最少一共有几只球? A) 11 B) 44

C) 55

D) 110

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2010年美国大学生数学建模竞赛B题一等奖

Summary Faced with serial crimes,we usually estimate the possible location of next crime by narrowing search area.We build three models to determine the geographical profile of a suspected serial criminal based on the locations of the existing crimes.Model One assumes that the crime site only depends on the average distance between the anchor point and the crime site.To ground this model in reality,we incorporate the geographic features G,the decay function D and a normalization factor N.Then we can get the geographical profile by calculating the probability density.Model Two is Based on the assumption that the choice of crime site depends on ten factors which is specifically described in Table5in this paper.By using analytic hierarchy process (AHP)to generate the geographical profile.Take into account these two geographical profiles and the two most likely future crime sites.By using mathematical dynamic programming method,we further estimate the possible location of next crime to narrow the search area.To demonstrate how our model works,we apply it to Peter's case and make a prediction about some uncertainties which will affect the sensitivity of the program.Both Model One and Model Two have their own strengths and weaknesses.The former is quite rigorous while it lacks considerations of practical factors.The latter takes these into account while it is too subjective in application. Combined these two models with further analysis and actual conditions,our last method has both good precision and operability.We show that this strategy is not optimal but can be improved by finding out more links between Model One and Model Two to get a more comprehensive result with smaller deviation. Key words:geographic profiling,the probability density,anchor point, expected utility

如何准备美国大学生数学建模比赛

如何准备美赛 数学模型:数学模型的功能大致有三种:评价、优化、预测。几乎所有模型都是围绕这三种功能来做的。比如,2012年美赛A题树叶分类属于评价模型,B题漂流露营安排则属于优化模型。 对于不同功能的模型有不同的方法,例如 评价模型方法有层次分析、模糊综合评价、熵值法等; 优化模型方法有启发式算法(模拟退火、遗传算法等)、仿真方法(蒙特卡洛、元胞自动机等); 预测模型方法有灰色预测、神经网络、马尔科夫链等。 在数学中国、数学建模网站上有许多关于这些方法的相关介绍与文献。 软件与书籍: 软件一般三款足够:Matlab、SPSS、Lingo,学好一个即可。 书籍方面,推荐三本,一本入门,一本进级,一本参考,这三本足够: 《数学模型》姜启源谢金星叶俊高等教育出版社 《数学建模方法与分析》Mark M. Meerschaert 机械工业出版社 《数学建模算法与程序》司守奎国防工业出版社 入门的《数学模型》看一遍即可,对数学模型有一个初步的认识与把握,国赛前看完这本再练习几篇文章就差不多了。另外,关于入门,韩中庚的《数学建模方法及其应用》也是不错的,两本书选一本阅读即可。如果参加美赛的话,进级的《数学建模方法与分析》要仔细研究,这本书写的非常好,可以算是所有数模书籍中最好的了,没有之一,建议大家去买一本。这本书中开篇指出的最优化模型五步方法非常不错,后面的方法介绍的动态模型与概率模型也非常到位。参考书目《数学建模算法与程序》详细的介绍了多种建模方法,适合用来理解模型思想,参考自学。 分工合作:数模团队三个人,一般是分别负责建模、编程、写作。当然编程的可以建模,建模的也可以写作。这个要视具体情况来定,但这三样必须要有人擅长,这样才能保证团队最大发挥出潜能。 这三个人中负责建模的人是核心,要起主导作用,因为建模的人决定了整篇论文的思路与结构,尤其是模型的选择直接关系到了论文的结果与质量。 对于建模的人,首先要去大量的阅读文献,要见识尽可能多的模型,这样拿到一道题就能迅速反应到是哪一方面的模型,确定题目的整体思路。 其次是接口的制作,这是体现建模人水平的地方。所谓接口的制作就是把死的方法应用到具体问题上的过程,即用怎样的表达完成程序设计来实现模型。比如说遗传算法的方法步骤大家都知道,但是应用到具体问题上,编码、交换、变异等等怎么去做就是接口的制作。往往对于一道题目大家都能想到某种方法,可就是做不出来,这其实是因为接口不对导致的。做接口的技巧只能从不断地实践中习得,所以说建模的人任重道远。 另外,在平时训练时,团队讨论可以激烈一些,甚至可以吵架,但比赛时,一定要保持心平气和,不必激烈争论,大家各让3分,用最平和的方法讨论问题,往往能取得效果并且不耽误时间。经常有队伍在比赛期间发生不愉快,导致最后的失败,这是不应该发生的,毕竟大家为了一个共同的目标而奋斗,这种经历是很难得的。所以一定要协调好队员们之间的关系,这样才能保证正常发挥,顺利进行比赛。 美赛特点:一般人都认为美赛比国赛要难,这种难在思维上,美赛题目往往很新颖,一时间想不出用什么模型来解。这些题目发散性很强,需要查找大量文献来确定题目的真正意图,美赛更为注重思想,对结果的要求却不是很严格,如果你能做出一个很优秀的模型,也许结果并不理想也可能获得高奖。另外,美赛还难在它的实现,很多东西想到了,但实现起来非常困难,这需要较高的编程水平。 除了以上的差异,在实践过程中,美赛和国赛最大的区别有两点: 第一点区别当然是美赛要用英文写作,而且要阅读很多英文文献。对于文献阅读,可以安装有道词典,

2018年美国“数学大联盟杯赛”(中国赛区)初赛三年级试卷及答案

2017-2018年度美国“数学大联盟杯赛”(中国赛区)初赛 (三年级) (初赛时间:2017年11月26日,考试时间90分钟,总分200分) 学生诚信协议:考试期间,我确定没有就所涉及的问题或结论,与任何人、用任何方式交流或讨论, 我确定我所填写的答案均为我个人独立完成的成果,否则愿接受本次成绩无效的处罚。 请在装订线内签名表示你同意遵守以上规定。 考前注意事项: 1. 本试卷是三年级试卷,请确保和你的参赛年级一致; 2. 本试卷共4页(正反面都有试题),请检查是否有空白页,页数是否齐全; 3. 请确保你已经拿到以下材料: 本试卷(共4页,正反面都有试题)、答题卡、答题卡使用说明、英文词汇手册、草稿纸。考试完毕,请务必将英文词汇手册带回家,上面有如何查询初赛成绩、及如何参加复赛的说明。其他材料均不能带走,请留在原地。 选择题:每小题5分,答对加5分,答错不扣分,共200分,答案请填涂在答题卡上。 1. 5 + 6 + 7 + 1825 + 175 = A) 2015 B) 2016 C) 2017 D) 2018 2.The sum of 2018 and ? is an even number. A) 222 B) 223 C) 225 D) 227 3.John and Jill have $92 in total. John has three times as much money as Jill. How much money does John have? A) $60 B) $63 C) $66 D) $69 4.Tom is a basketball lover! On his book, he wrote the phrase “ILOVENBA” 100 times. What is the 500th letter he wrote? A) L B) B C) V D) N 5.An 8 by 25 rectangle has the same area as a rectangle with dimensions A) 4 by 50 B) 6 by 25 C) 10 by 22 D) 12 by 15 6.What is the positive difference between the sum of the first 100 positive integers and the sum of the next 50 positive integers? A) 1000 B) 1225 C) 2025 D) 5050 7.You have a ten-foot pole that needs to be cut into ten equal pieces. If it takes ten seconds to make each cut, how many seconds will the job take? A) 110 B) 100 C) 95 D) 90 8.Amy rounded 2018 to the nearest tens. Ben rounded 2018 to the nearest hundreds. The sum of their two numbers is A) 4000 B) 4016 C) 4020 D) 4040 9.Which of the following pairs of numbers has the greatest least common multiple? A) 5,6 B) 6,8 C) 8,12 D) 10,20 10.For every 2 pencils Dan bought, he also bought 5 pens. If he bought 10 pencils, how many pens did he buy? A) 25 B) 50 C) 10 D) 13 11.Twenty days after Thursday is A) Monday B) Tuesday C) Wednesday D) Thursday 12.Of the following, ? angle has the least degree-measure. A) an obtuse B) an acute C) a right D) a straight 13.Every student in my class shouted out a whole number in turn. The number the first student shouted out was 1. Then each student after the first shouted out a number that is 3 more than the number the previous student did. Which number below is a possible number shouted out by one of the students? A) 101 B) 102 C) 103 D) 104 14.A boy bought a baseball and a bat, paying $1.25 for both items. If the ball cost 25 cents more than the bat, how much did the ball cost? A) $1.00 B) $0.75 C) $0.55 D) $0.50 15.2 hours + ? minutes + 40 seconds = 7600 seconds A) 5 B) 6 C) 10 D) 30 16.In the figure on the right, please put digits 1-7 in the seven circles so that the three digits in every straight line add up to 12. What is the digit in the middle circle? A) 3 B) 4 C) 5 D) 6 17.If 5 adults ate 20 apples each and 3 children ate 12 apples in total, what is the average number of apples that each person ate? A) 12 B) 14 C) 15 D) 16 18.What is the perimeter of the figure on the right? Note: All interior angles in the figure are right angles or 270°. A) 100 B) 110 C) 120 D) 160 19.Thirty people are waiting in line to buy pizza. There are 10 people in front of Andy. Susan is the last person in the line. How many people are between Andy and Susan? A) 18 B) 19 C) 20 D) 21

2018年美国“数学大联盟杯赛”(中国赛区)初赛五年级试卷(1)

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