2015年数模美赛ABCD题目

Problem A Warmer Days or Sour Grapes ?The high quality of wines（葡萄酒）produced in the Finger Lakes Region（五指湖区）of upstate （北部）New York is widely known. Proximity（接近）to lakes tempers the climate and makes it more suitable for growing several varieties of premium（独特）grapes: R iesling（雷司令）, G ewürztraminer（琼瑶浆）,C hardonnay（霞多丽）, M erlot（梅洛）, P inot Noir（黑比诺）, and CabernetF ranc（品丽珠）. (There are many more, but we will restrict（限制）the discussion to these six to simplify（简化）the modeling.) Each variety has its own preferred “average temperature” range but is also different in its susceptibility（感受性）to diseases and ability to withstand（抵抗）short periods of unusually cold temperature.As our local climate changes, the relative suitability of these varieties will be changing as well. A forward-looking winery（酒厂）has hired your team to help with the long-term planning. You will need to recommenda) the proportion（比例）of the total vineyard（葡萄园）to be used for growing each of the above six varieties;b) and when should these changes be implemented （实施）(based on observed temperatures and/or current market prices for each type of wine).Naturally, the winery is interested in maximizing its annual profit. But since the latter （后者）is weather-dependent, it might vary a lot year-to-year. You are also asked to evaluate the trade-offs （权衡）between optimizing the expected/average case versus the worst(-realistic-)scenario（情景）.Things to keep in mind:Climate modeling is complicated（复杂）and predicting the rate of “global warming” is a hotly debated area. For the purposes of this problem, assume that the annual average temperature in Ithaca（伊萨卡）, NY will increase by no more than 4°C by the end of this century.It is not all about the average temperature – a short snap（临时）of sub- zero（零度）temperature in late Ferburay or early March (after the vines already started getting used to warmer weather) is far more damaging than the same low temperature would be in the middle of the winter.It takes at least 3 years for a newly planted vine to start producing grapes suitable for winemaking.Problem B Outlook of Car-to-Car TechSAN FRANCISCO -- After more than a decade of research into car-to-car communications, U.S. auto safety regulators took a step forward today by unveiling their plan for requiring cars to have wireless gear that will enable them to warn drivers of danger.These vehicle-to-vehicle (V2V) transmitters and software could save thousands of lives and prevent hundreds of thousands of crashes each year by providing cars with information they never will be able to gather simply from cameras and sensors. “Safety is our top priority, and V2V technology represents the next great advance in saving lives,” Transportation Secretary Anthony Foxx said in an announcement. “This technology could move us from helping people survive crashes to helping them avoid crashes altogether.”Requirement 1: Present a mathematical model to discuss the reduction of the number of traffic accidents and road fatalities/injuries in San Francisco by V2V technology. Requirement 2: Determine the maximum number of cars in San Francisco due to the V2V technology.Requirement 3: Discuss the benefits of V2V technology to alleviate road congestion. Requirement 4: Provide your recommendation to the government.Prblem C Forest FiresOne major environmental concern is the occurrence of forest fires (also called wildfires), which affect forest preservation, bring economical and ecological damage and endanger human lives. Such phenomenon is due to multiple causes (e.g. human negligence and lightnings). Despite an increasing of state expenses to control this disaster, each year millions of forest hectares (ha) are destroyed all around the world.Fast detection is an important element for successful firefighting. Traditional human surveillance is expensive and affected by subjective factors, there has been an emphasis to develop automatic solutions, such as satellite-based, infrared/smoke scanners and local sensors (e.g. meteorological). Propagation models try to describe the future evolution of the forest fire given an initial scenario and certain input parameters. Modeling the dynamical behavior of fire propagation in a forest is helpful for creating scheme to control and fight fire.Requirement 1 Describe several different metrics that could be used to evaluate the effectiveness of fire detection. Could you combine your metrics to make them even more useful for measuring quality?Requirement 2 Model the dynamical behavior of fire spread in a forest. Requirement 3 Discuss the factors to affect fire occurrence. Which factors are the most critical in causing fires. Build mathematical models to predict the burned area of fires using Meteorological Data.Requirement 4 Give y our suggestion for preventing from forest fire and fighting against it.Problem D Wearable Activity RecognitionThe percentage of EU citizens aged 65 years or over is projected to increase from 17.1% in 2008 to 30.0% in 2060. In particular, the number of 65 years old is projected to rise from 84.6 million to 151.5 million, while the number of people aged 80 or over is projected to almost triple from 21.8 million to 61.4 million (EUROSTAT: New European Population projections 2008–2060). It has been calculated that the purely demographic effect of an ageing population will push up health-care spending by between 1% and 2% of the gross domestic product (GDP) of most member states. At first sight this may not appear to be very much when extended over several decades, but on average it would in fact amount to approximately a 25% increase in spending on health care, as a share of GDP, in the next 50 years (European Economy Commission, 2006). The effective incorporation of technology into health-care systems could therefore be decisive in helping to decrease overall public spending on health. One of these emerging health-care systems is daily living physical activity recognition.Daily living physical activity recognition is currently being applied in chronic disease management (Amft & Troter, 2008; Zwartjes, Heida, van Vugt, Geelen, & Veltink, 2010), rehabilitation systems (Sazonov, Fulk, Sazonova, & Schuckers, 2009) and disease prevention (Sazonov, Fulk, Hill, Schutz, & Browning, 2011; Warren et al., 2010), as well as being a personal indicator to health status (Arcelus et al., 2009). One of the principal subjects of the health related applications being mooted is the monitoring of the elderly. For example, falls represent one of the major risks and obstacles to old people’s independence (Najafi, Aminian, Loew, Blanc, & Robert, 2002; Yu, 2008). This risk is increased when some kind of degenerative disease affects them. Most Alzheimer’s patients, for exa mple, spend a long time every day either sitting or lying down since they would otherwise need continuous vigilance and attention to avoid a fall.The registration of daily events, an important task in anticipating and/or detecting anomalous behavior patterns and a primary step towards carrying out proactive management and personalized treatment, is normally poorly accomplished by patients’ families, healthcare units or auxiliary assistants because of limitations in time and resources. Automatic activity-recognition systems could allow us to conduct a completely detailed monitoring and assessment of the individual, thus significantly reducing current human supervision requirements.Most wearable activity recognition systems assume a predefined sensor deployment that remains unchanged during runtime. However, this assumption does not reflect real-life conditions. During the normal use of such systems, users may place the sensors in a position different from the predefined sensor placement. Also, sensors may move from their original location to a different one, due to a loose attachment. Activity recognition systems trained on activity patterns characteristic of a given sensor deployment may likely fail due to sensor displacements.Your task is as follows.(1) Build models to recognize daily living activities.(2) Explore the effects of sensor displacement induced by both the intentionalmisplacement of sensors and self-placement by the user.(3) Verify your recognition models’ toleranc e to sensor displacement.Data Set Information:The REALDISP (REAListic sensor DISPlacement) dataset has been originally collected to investigate the effects of sensor displacement in the activity recognition process in real-world settings. It builds on the concept of ideal-placement, self-placement and induced- displacement. The ideal and mutual-displacement conditions represent extreme displacement variants and thus could represent boundary conditions for recognition algorithms. In contrast, self-placement reflects a users perception of how sensors could be attached, e.g., in a sports or lifestyle application. The dataset includes a wide range of physical activities (warm up, cool down and fitness exercises), sensor modalities (acceleration, rate of turn, magnetic field and quaternions) and participants (17 subjects). Apart from investigating sensor displacement, the dataset lend itself for benchmarking activity recognition techniques in ideal conditions.Dataset summary:#Activities: 33#Sensors: 9#Subjects: 17#Scenarios: 3ACTIVITY SET:A1: WalkingA2: JoggingA3: RunningA4: Jump upA5: Jump front & backA6: Jump sidewaysA7: Jump leg/arms open/closedA8: Jump ropeA9: Trunk twist (arms outstretched)A10: Trunk twist (elbows bent)A11: Waist bends forwardA12: Waist rotationA13: Waist bends (reach foot with opposite hand)A14: Reach heels backwardsA15: Lateral bend (10_ to the left + 10_ to the right)A16: Lateral bend with arm up (10_ to the left + 10_ to the right)A17: Repetitive forward stretchingA18: Upper trunk and lower body opposite twistA19: Lateral elevation of armsA20: Frontal elevation of armsA21: Frontal hand clapsA22: Frontal crossing of armsA23: Shoulders high-amplitude rotationA24: Shoulders low-amplitude rotationA25: Arms inner rotationA26: Knees (alternating) to the breastA27: Heels (alternating) to the backsideA28: Knees bending (crouching)A29: Knees (alternating) bending forwardA30: Rotation on the kneesA31: RowingA32: Elliptical bikeA33: CyclingSENSOR SETUP:Each sensor provides 3D acceleration (accX,accY,accZ), 3D gyro (gyrX,gyrY,gyrZ), 3D magnetic field orientation (magX,magY,magZ) and 4D quaternions (Q1,Q2,Q3,Q4). The sensors are identified according to the body part on which is placed respectively:。

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地球资源的消耗速度快,越来越多的人关注人类社会的未来.自1960年以来，已经有许多专家研究可持续发展.然而大多数人的研究对象是整个世界，一个国家或一个地区。

几乎没有人选择48个最不发达国家(LDC)在联合国为研究对象列表。

然而,LDC国家集团共享许多相同的点。

他们的发展道路也有法律的内涵。

本文选择这些国家为研究对象针对发现常规的可持续发展道路。

本文组织如下.第二部分介绍研究的背景和本研究的意义。

第三节描述了我们对可持续发展的理解细节和显示我们的评估系统的建立过程和原理，那么我们估计每一个国家的LDC和获得可持续发展的能力和等级。

第四节提供了一个最糟糕的国家毛里塔尼亚计划指数在第三节。

第五节演示了在第四节的合理性和可用性计划。

最后在第六节总结本文的主要结论和讨论的力量和潜在的弱点。

地球上的资源是有限的。

三大能源石油、天然气和煤炭可再生。

如何避免人类的发展了资源枯竭和实现可持续发展目标是现在的一个热门话题.在过去的两个世纪,发达国家已经路上,先污染，再控制和达到高水平的可持续发展。

发展中国家希望发展和丰富。

然而,因为他们的技术力量和低水平的经济基础薄弱,浪费和低效率的发展在这些国家是正常的.所以本文主要关注如何帮助发展中国家特别是48在联合国最不发达国家实现可持续发展是列表可持续发展的理解是解决问题的关键.可持续发展的定义经历了一个长期发展的过程.在这里，布伦特兰可持续发展委员会的简短定义的"能力发展可持续- — - — - -以确保它既满足现代人的需求又不损害未来的能力代来满足自己的需求"［1]无疑是最被广泛接受的一个在各种内吗定义.这个定义方面发挥了重要作用在很多国家的政策制定的过程.然而，为了证明一个国家的现状是否可持续不可持续的,更具体的定义是必要的更具体的概念,我们认为,如果一个国家的发展是可持续的,它应该有一个基本的目前的发展水平，一个平衡的国家结构和一个光明的未来。

2015年美国大学生数学建模竞赛赛题翻译2015年美国大学生数学竞赛正在进行，比赛时间为北京时间：20１5年2月６日(星期五)上午9点—２月10日上午9点.竞赛以三人(本科生）为一组，在四天时间内,就指定的问题，完成该实际问题的数学建模的全过程,并就问题的重述、简化和假设及其合理性的论述、数学模型的建立和求解(及软件)、检验和改进、模型的优缺点及其可能的应用范围的自我评述等内容写出论文。

2０15 ＭＣM/ICM Ｐｒｏblems总计4题，参赛者可从MＣM Pｒoｂlｅm A, MＣM Problem B，ICM Pｒoblem C oｒICM Ｐｒｏbｌem D等四道赛题中自由选择。

201５Contest ProｂｌemsMCM ＰROBLEMSPROBLEM A: Erａdiｃating EbｏlaThe wｏrｌｄmedical assoｃiatiｏn has ａnnounced that ｔheｉｒneｗmｅdiｃatioｎcouｌd stop Ｅbola anｄcｕｒｅｐａtｉents ｗhose dｉsease ｉs not aｄｖanced. Ｂuild a realistｉc, sensｉblｅ, ａnｄusefｕｌmodel thaｔｃｏnsiders not onlｙｔhｅsｐｒead of the dｉsease，ｔｈｅqｕaｎtｉｔy of ｔhｅmedｉcine needed，ｐｏｓsｉble ｆeasible delivｅｒy sysｔemｓ（seｎdiｎg ｔhe meｄiｃine to where iｔis neｅdｅｄ), （gｅｏgrａphiｃal）loｃatioｎs of ｄelｉvery，ｓｐeed of mａｎufacturing of tｈe ｖa ｃcine ｏｒｄruｇ, but also ａｎy oｔheｒcriticａl factors your ｔeam cｏnｓidｅrs ｎecessaｒｙas ｐarｔｏf thｅｍodel to ｏpｔimize thｅerａdicaｔioｎoｆEｂola，oｒａt lｅａｓt ｉts current sｔrain. Iｎadd ｉtion ｔo your ｍodｅling apprｏach fｏr thｅcontest, prepare ａ１—2 page ｎon-teｃｈnical ｌettｅr for ｔhe wｏrld ｍｅｄicaｌａｓsocｉation ｔｏuse ｉｎtheir announｃｅmｅｎt．中文翻译：问题一：根除埃博拉病毒世界医学协会已经宣布他们的新药物能阻止埃博拉病毒并且可以治愈一些处于非晚期疾病患者。

PROBLEM A: Eradicating（根除）EbolaThe world medical association has announced that their new medication could stop Ebola and cure patients whose disease is not advanced（晚期的）. Build a realistic, sensible, and useful model that considers not only the spread of the disease, the quantity of the medicine needed, possible feasible （可行的）delivery systems, locations of delivery, speed of manufacturing of the vaccine or drug, but also any other critical factors your team considers necessary as part of the model to optimize the eradication of Ebola, or at least its current strain（压力）. In addition to your modeling approach for the contest, prepare a 1-2 page non-technical letter for the world medical association to use in their announcement.PROBLEM B: Searching for a lost planeRecall the lost Malaysian flight MH370. Build a generic（一般的）mathematical model that could assist "searchers" in planning a useful search for a lost plane feared to（恐怕） have crashed in open water such as the Atlantic, Pacific, Indian, Southern, or Arctic Ocean while flying from Point A to Point B. Assume that there are no signals from the downed （坠落的） plane. Your model should recognize that there are many different types of planes for which we might be searching and that there are many different types of search planes, often using different electronics or sensors. Additionally, prepare a 1-2 page non-technical paper for the airlines to use in their press conferences concerning their plan for future searches.。

比赛时间：美国东部时间：2015年2月5日（星期四）下午8点-2月9日下午8点（共4天）北京时间：2015年2月6日（星期五）上午9点-2月10日上午9点农历：十二月十八～十二月廿二重要说明：●COMAP是所有的规则和政策的最后仲裁者，对不遵循竞赛规则和程序的任何队伍，拥有唯一的自由裁量权，取消参赛资格或拒绝登记。

●评委、竞赛组织者、以及UMAP杂志的编辑拥有最终裁定权。

●如果参赛队伍违反竞赛规则，其指导老师一年内将不能指导其他团队，其所在参赛单位将被处以一年的察看处理。

●如果同一机构第二次被抓到违反规则的队伍，该学校将至少不被允许参加下一年度的赛事。

●以下所有时间都是美国东部时间EST（北京时间比美国东部时间早13个小时）●递交参赛论文后，意味参赛者同意以下条款：⏹论文提交后，出版权归COMAP, Inc所有；⏹COMAP可以使用，编辑，引用和出版论文，用于宣传或任何其他目的，包括在线展示，出版电子版，在UMAP杂志刊登或其他方式，并且没有任何形式的补偿；⏹COMAP可以在没有进一步的通知，许可，或补偿的情形下，使用这次比赛相关材料，团队成员、指导老师的名字，以及和他们的背景资料。

●递交参赛论文后，意味参赛者作出以下承诺：⏹论文中出现的所有的图像，数据，照片，图表，图画，如果未注明，都是由参赛者创建；如果引用其它资源，都在参考文献中列出，并在引用的具体位置标注来源。

⏹不论是直接，还是转述方式的文字引用，都在参考文献中列出，并在引用的具体位置标注来源；直接的文字引用使用引号标注。

比赛之前注册报名1.报名截至时间：2015年2月5日下午2：00 EST。

截止日期后，注册系统将自动关闭，不再接受任何新的注册，没有例外。

2.每支参赛队伍都必须有一位来自参赛机构（institute）的教师担任导师（faculty advisor），不允许学生担任导师。

由指导老师负责为其指导队伍注册报名，每位指导老师可注册的队伍数目没有限制。

太阳影子定位技术问题的数学模型摘要本文涉及的是太阳影子定位技术问题。

在已知视频中物体的太阳影子变化的情况下，要确定视频的拍摄地点和拍摄日期。

首先，分析了文中四个问题的关系，发现前三个问题的已知条件逐步减少，问题难度依次递进。

第四问则给出一个实际问题，该问题需要转化成数学模型利用前三问的方法求解；随后，建立了L-G模型、MinZ-模型等，并应用非线性最小二乘法、遗传算法等算法对模型求解。

得到基于模型的合理结果。

最后，将第四问的实际问题转化数学模型并求解，进而解决问题。

对于问题一，要解决的问题是杆长与影子长度的关系，根据天文、几何知识，我们建立了模型来刻画问题给出的参数之间联系，如赤纬角模型、时角模型、太阳高度角模型、影子长度模型（L-G模型）等；分析了各参数对影子长度的影响；最后运用MATLAB绘制出具体给定参数下的3米高直杆的影子变化曲线；从曲线可以看出在9:00到15:00这段时间里，影子长度先变短后变长，最短为3.627米，最长为7.182米。

问题二提供了一个关于时间、影子坐标的附件1，杆长未知，为了确定直杆所处的地点，本问建立了MinZ-模型，首先将经度、纬度、杆长离散化，搜索出大概的可行解，然后运用非线性最小二乘算法，选取matlab中的lsqcurvefit命令，以可行解为初值，再运用非线性最小二乘算法，选取MATLAB中的lsqcurvefit命令，在控制残差在10−8之内范围的情况下得到了三个可能地点皆在海南省昌江县内，最小误差的地点为海南省江黎族自治县，北纬19.3025°，东经108.6988°，此时对应直杆高度为2.0219m。

同时，将结果代入问题一的模型进行检验，验证了模型的稳定性和算法的合理性。

问题三沿用问题一的模型和问题二的算法，由于一个已知量变成一个变量，根据算法特点，在增加一个变量的情况下，算法搜索影长差时只需要增加一重循环。

关于附件2数据，残差最小对应的位置为北纬39.8926°，东经79.7438°，具体地点在新疆维吾尔自治区喀什地区巴楚县。

2015 Contest ProblemsMCM PROBLEMSPROBLEM A: Eradicating EbolaThe world medical association has announced that their new medication could stop Ebola and cure patients whose disease is not advanced. Build a realistic, sensible, and useful model that considers not only the spread of the disease, the quantity of the medicine needed, possible feasible delivery systems, locations of delivery, speed of manufacturing of the vaccine or drug, but also any other critical factors your team considers necessary as part of the model to optimize the eradication of Ebola, or at least its current strain. In addition to your modeling approach for the contest, prepare a 1-2 page non-technical letter for the world medical association to use in their announcement.PROBLEM B: Searching for a lost planeRecall the lost Malaysian flight MH370. Build a generic mathematical model that could assist "searchers" in planning a useful search for a lost plane feared to have crashed in open water such as the Atlantic, Pacific, Indian, Southern, or Arctic Ocean while flying from Point A to Point B. Assume that there are no signals from the downed plane. Your model should recognize that there are many different types of planes for which we might be searching and that there are many different types of search planes, often using different electronics or sensors. Additionally, prepare a 1-2 page non-technical paper for the airlines to use in their press conferences concerning their plan for future searches.ICM PROBLEMSPROBLEM C: Managing Human Capital in OrganizationsClick the title below to download a PDF of the 2015 ICM Problem C.Your ICM submission should consist of a 1 page Summary Sheet and your solution cannot exceed 20 pages for a maximum of 21 pages.Managing Human Capital in OrganizationsPROBLEM D: Is it sustainable?Click the title below to download a PDF of the 2015 ICM Problem D.Your ICM submission should consist of a 1 page Summary Sheet and your solution cannot exceed 20 pages for a maximum of 21 pages.Is it sustainable?。

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。

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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) 1B) 2C) 3D) 4 or more3. If I answered 34 out of 40 questions on my math test correctly, I answered ? % of the questions correctly.A) 75B) 80 C) 85 D) 904. 120 ÷ 3 ÷ 4 × 12 =A) 1 B) 10 C) 12 D) 120 5. 10 × 20 × 30 × 40 = 24 × ?A) 1000B) 10 000C) 100 000D) 1000 0006. 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) 19B) 20C) 21D) 227. 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 ofA) -40 B) -4 C) 4 D) 80 9. Which of the following numbers has exactly 3 positive divisors?A) 49B) 56C) 69D) 10010. 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) 4B) 5C) 6D) 711. 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) 210B) 215C) 221D) 212014. 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 beA) odd B) even C) 11 D) 1716. If a and b are positive integers such that a /b = 5/7, then a + b isA) 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) 3B) 365 C) 1095 D) 3285 18. If the current month is February, what month will it be 1 199 999 months from now?A) JanuaryB) FebruaryC) MarchD) April19. 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) 30B) 60C) 90D) 12022. 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) 11B) 22C) 33D) 4423. John wrote a number whose digits consists entirely of 1s. This number was a composite number. His number could contain exactly ? 1s.A) 17B) 19C) 29D) 3224. 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) 3625. 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第1页，共4页A) 4V B) V/2 C) V D) 2V26.Rick and Roy each stands at different ends of a straight road that is 64 m long. They runtoward 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) 827.If the area of a certain circle is 2016, its radius isA) sqrt(2016/π) B) sqrt(4032/π)C) 2016/πD) 1008/π28.In a toy shop, the cost of a Teddy Bear is 200% as much as that of a toy train. The cost ofa toy train is 6/5 the cost of a pack of the wooden blocks. The cost of a pack of woodenblocks is $50. What is the cost, in dollars, of the Teddy Bear?A) 60 B) 100 C) 120 D) 20029.In the sequence 2016, 225, 141, 66, 432, 99, 1458 …, each term after the first term is thesum of the cubes of the digits of the previous term. What is the 100th term of thissequence?A) 153 B) 351 C) 370 D) 37130.What is the sum of all the positive divisors of 210?A) 210 – 1 B) 211 – 1 C) 212 – 1 D) 213 – 131.It takes 4 hours for Mike and Lucy to finish a task. It takes Lucy and Jerry 5 hours tofinish 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) 632.If you sell a cloth at its current price, you get $40 profit. The total profit you get selling 10clothes 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) 12533.There are 6 identical squares in the figure on the right. The side length of eachsquare is 1. Of all the triangles constructed by connecting three of the 18vertices in the figure, how many of them are triangles whose area is 2 andwhich has at least one vertical or horizontal side?A) 12 B) 16 C) 24 D) 2834.Pick up N numbers from 1 to 2015 inclusively, such that the sum of any three of the Nnumbers is divisible by 24. What is the maximum value of N?A) 83 B) 84 C) 168 D) 25235.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) $8036.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。

初二年级初赛试题姓名_____________ 学校_____________ 得分____________ 一、填空题Ⅰ（每小题6分，共60分）1. 三角形的两条中线长分别为6和9，如果第三边长为整数，那么其最大值为答案：9 解答：如图，根据重心定理得到OB =6，OC =4，BC <4+6=10，故第三边长最大值为2. 如图，小正方形的面积为2，弓形过A 、B 、C 三个格点，那么这个弓形的面积为___________；答案：5.7解答：如图，圆心在O 处，OC =∠AOC =90°,2211=510 5.742S ππ-=-=阴.3. 在梯形ABCD 中，AB //CD ，∠A =90°，AB =2，BC =3，E 是AD 的中点，BE 平分∠ABC ，则①CD =1；②CE ⊥BE ；③CE 平分∠BCD ；④12BCE S S ∆=梯形；⑤BE ．成立的结论共有___________个；答案：5解答：5个结论都对．4. 分解因式：22(1)(2)12x x x x ++++-=___________；答案：2(1)(2)(5)x x x x -+++解答：原式=222(1)(1)12x x x x +++++- =22(14)(13)x x x x +++++- =2(1)(2)(5)x x x x -+++5. 一个凸多边形的内角均不相等，按从小到大排列后，最小的内角为120°，每一个都比前一个大5°，则这个多边形的对角线为___________条； 答案：27解答：设这个多边形为凸n 边形，(1)1205(2)1802120(1)5180n n n n n -⎧+⨯=-⨯⎪⎨⎪+-⨯<⎩，解得n =9，对角线有9⨯6÷2=27条．6. 如图，正方形ABCD 和菱形DBEF ，延长FE 过C 点，则∠EBC =___________度； 答案：15解答：如图，连结AC 交BD 于O ，过E 作EG ⊥BD 于G ，可以得到12GE BE =，所以∠EBD =30°，∠EBC =45°-30°=15°．7. 正整数m 、n满足915m n +-=___________；答案：3解答：2150--=3)0=30+>5=所以，41m n =⎧⎨=⎩原式=22+31+42412⨯⨯⨯-+=3．8. 如图，一牧童在A 处放马，牧童家在B 处，A 、B 到河岸CD 的距离分别为500米和700米，且CD 长为500米，天黑前牧童从A 点将马牵到河边饮水，再赶回家，那么牧童最少要走_________米； 答案：1300解答：如图，作点A 关于河边的对称点E ，连结BE ，过E 作EF ⊥BF 于根据勾股定理得到BE =1300，即牧童最少走1300米．9. 已知2a ≤，3b ≤，6c ≤，且214a b c --=，则201320142015a b c⨯=答案：112-解答：222223614a b c a b c a b c --≤++≤++≤+⨯+=，当且仅当b 、c 同号、a 与它们异号时取等号．1）当a =2、b =-3、c =-6时，原式=1232(3)1(6)12⨯-=--； 2）当a =-2、b =3、c =6时，原式=123(2)31612-⨯=-． 综上所述：原式=112-．10. 一个直角三角形的两条边之差为2，另一边长为10，那么这个三角形的周长为___________；答案：24或60解答：设其中一边为x ，222(2)10x x ++=或22210(2)x x +=+ 解得x =6或x =24，求得周长为24或60．二、填空题Ⅱ（每小题8分，共40分）11. 如图，在Rt △ABC 中，∠ACB =90°,M 、N 分别为AB 的三等分点，且CM=，CN=，那么△ABC 的面积为___________cm 2；答案：解答：如图，分别过M 、N 作BC 的垂线，交BC 于D 、E ，设BE =x ，NE =y ， 利用勾股定理列方程组．2222448427x y x y ⎧+=⎪⎨+=⎪⎩，解得正数解2x y =⎧⎪⎨⎪⎩ABC 的面积为(2⨯3)⨯(32=12.已知2013M ++，48124028=13355720132015N -+-+⨯⨯⨯⨯，那么2(21)2M N +=___________；答案：1008解答：2015M ++ 111111111201611335572013201520152015N ⎛⎫⎛⎫⎛⎫⎛⎫=+-+++-++=+= ⎪ ⎪ ⎪ ⎪⎝⎭⎝⎭⎝⎭⎝⎭ABC MNAB CMND E原式=20162015201510082⨯=．13. 已知22()()2015c a b b a c +=+=，且b c ≠，则abc =___________；答案：-2015解答：由b c ≠，22()()()()0c a b b a c c b ab ac bc +-+=-++=，得到0ab ac bc ++=，所以2()()2015abc ac bc c c a b =--=-+=-．14. 如图，矩形ABCD 的对角线相交于点O ，AE 平分∠BAD 交BC 于E ，∠CAE =15°，则∠AOE =___________°； 答案：135解答：可证△AOB 为等边三角形，△BOE 为等腰三角形，0006075135AOE ∠=+=．15. 像三棱锥、长方体、五棱台等都是简单的几何体，又叫做多面体，著名的数学家欧拉发现这些多面体的顶点数（V ）、面数（F ）、棱数（E ）之间的规律为V +F -E =2．根据这个规律，若一个多面体恰好由一些正五边形和正六边形构成，则这个多面体是___________面体；答案：32解答：设正五边形有x 个，正六边形有y 个，1156(56)231(56)22V x y x y E x y F x y V F E ⎧==⨯=+⎪⎪⎪=+⎨⎪=+⎪⎪+-=⎩，解得1220x y =⎧⎨=⎩，所以这个多面体共12+20=32个面．。