87994.com

学习资料共享网 文档搜索专家

学习资料共享网 文档搜索专家

2015 AMC 12B 竞赛真题

Problem 1

What is the value of ?

Problem 2

Marie does three equally time-consuming tasks in a row without taking breaks. She begins the first task

at 1:00 PM and finishes the second task at 2:40 PM. When does she finish the third task?

Problem 3

Isaac has written down one integer two times and another integer three times. The sum of the five numbers is 100, and one of the numbers is 28. What is the other number?

Problem 4

David, Hikmet, Jack, Marta, Rand, and Todd were in a 12-person race with 6 other people. Rand finished 6 places ahead of Hikmet. Marta finished 1 place behind Jack. David finished 2 places behind Hikmet. Jack finished 2 places behind Todd. Todd finished 1 place behind Rand. Marta finished in 6th place. Who finished in 8th place?

Problem 5

1/8

2015 年 AMC12B

The Tigers beat the Sharks 2 out of the 3 times they played. They then played more times, and the Sharks ended up winning at least 95% of all the games played. What is the minimum possible value for ?

Problem 6

Back in 1930, Tillie had to memorize her multiplication facts from to . The multiplication table she was given had rows and columns labeled with the factors, and the products formed the body of the table. To the nearest hundredth, what fraction of the numbers in the body of the table are odd?

Problem 7

A regular 15-gon has lines of symmetry, and the smallest positive angle for which it has rotational symmetry is degrees. What is ?

Problem 8

What is the value of ?

Problem 9

Larry and Julius are playing a game, taking turns throwing a ball at a bottle sitting on a ledge. Larry throws first. The winner is the first person to knock the bottle off the ledge. At each turn the probability that a player knocks the bottle off the ledge is , independently of what has happened before. What is the probability that

Larry wins the game?

2/8 2015 年 AMC12B

Problem 10

How many noncongruent integer-sided triangles with positive area and perimeter less than 15 are neither equilateral, isosceles, nor right triangles?

Problem 11

The line forms a triangle with the coordinate axes. What is the sum of the lengths of the altitudes of this triangle?

Problem 12

Let , , and be three distinct one-digit numbers. What is the maximum value ?

of the sum of the roots of the equation

Problem 13

Quadrilateral is inscribed in a circle with and . What is ?

Problem 14

A circle of radius 2 is centered at . An equilateral triangle with side 4 has a vertex at . What is the difference between the area of the region that lies inside the circle but outside the triangle and the area of the region that lies inside the triangle but outside the circle?

3/8 2015 年 AMC12B

Problem 15

At Rachelle's school an A counts 4 points, a B 3 points, a C 2 points, and a D 1 point. Her GPA on the four classes she is taking is computed as the total sum of points divided by 4. She is certain that she will get As in both Mathematics and Science, and at least a C in each of English and History. She thinks she has a chance of getting an A in English, and a has a chance of getting an A, and a chance of getting a B. In History, she chance of getting a B, independently of

what she gets in English. What is the probability that Rachelle will get a GPA of at least 3.5?

Problem 16

A regular hexagon with sides of length 6 has an isosceles triangle attached to each side. Each of these triangles has two sides of length 8. The isosceles triangles are folded to make a pyramid with the hexagon as the base of the pyramid. What is the volume of the pyramid?

Problem 17

An unfair coin lands on heads with a probability of . When tossed times, the

probability of exactly two heads is the same as the probability of exactly three heads. What is the value of ?

4/8

2015 年 AMC12B

Problem 18

For every composite positive integer in the prime factorization of factorization of function , is , define to be the sum of the factors because the prime . What is the range of the ?

. For example, , and

Problem 19

In , and . Squares constructed outside of the triangle. The points , What is the perimeter of the triangle? , and , and are lie on a circle.

Problem 20

For every positive integer , let be the remainder obtained when is

divided by 5. Define a function recursively as follows:

What is

5/8

?

2015 年 AMC12B

Problem 21

Cozy the Cat and Dash the Dog are going up a staircase with a certain number of steps. However, instead of walking up the steps one at a time, both Cozy and Dash jump. Cozy goes two steps up with each jump (though if necessary, he will just jump the last step). Dash goes five steps up with each jump (though if necessary, he will just jump the last steps if there are fewer than 5 steps left). Suppose that Dash takes 19 fewer jumps than Cozy to reach the top of the staircase. Let denote the sum of all possible numbers of steps this staircase can have. What is the sum of the digits of ?

Problem 22

Six chairs are evenly spaced around a circular table. One person is seated in each chair. Each person gets up and sits down in a chair that is not the same chair and is not adjacent to the chair he or she originally occupied, so that again one person is seated in each chair. In how many ways can this be done?

Problem 23

A rectangular box measures , where , , and are integers and . The volume and the surface area of the box are numerically equal. How many ordered triples are possible?

Problem 24

Four circles, no two of which are congruent, have centers at and points and lie on all four circles. The radius of circle , and the radius of circle is , is , , and times the . ,

radius of circle

times the radius of circle

6/8

2015 年 AMC12B

Furthermore, What is

and ?

. Let

be the midpoint of

.

Problem 25

A bee starts flying from point . She flies inch due east to point . For , once the bee reaches point , she turns counterclockwise and then flies inches straight to point . When the bee reaches she is exactly integers and and ? inches away from , where , , and are positive

are not divisible by the square of any prime. What is

7/8

2015 年 AMC12B

2015 AMC 12B 竞赛真题答案

1.C 11.e 21.d

2.b 12.d 22.d

3.a 13.b 23.b

4.b 14.d 24.d

5.b 15.d 25.b

6.a 16.c

7.d 17.d

8.d 18.d

9.c 19.c

10.c 20.b

8/8

2015 年 AMC12B

相关文章:

- 美国数学竞赛真题及答案
- 美国数学
*竞赛真题及答案*_高三数学_数学_高中教育_教育专区。2014 年美国高中数学竞赛(*AMC12*)B 卷试题及解答 解答:选 C, 设∠DHG=∠JAG=∠KJE=θ,由 KJ=HG=...

- 2013年AMC12B竞赛真题及答案_图文
- 2013
*年AMC12B竞赛真题及答案*_学科竞赛_小学教育_教育专区。2013 年 AMC 12B ...文档贡献者 fishernj 贡献于*2015*-09-04 1/2 相关文档推荐 2013年全国大学生...

- 2014-2015年度全美数学竞赛_图文
- 2014-
*2015*年度全美数学竞赛_学科竞赛_小学教育_教育专区。2014-*2015*年度全美数学竞赛 双击图片,修改大小即可放大看*2015**AMC*美国数学*竞赛试题及答案*2014 年度全美...

- 2016 AMC 12B 试题及解答
- 2016
*AMC 12B**试题及*解答_学科*竞赛*_高中教育_教育专区 暂无评价|0人阅读|0次下载|举报文档2016*AMC 12B**试题及*解答_学科*竞赛*_高中教育_教育专区。2016*AMC 12B*...

- 2015 AMC 12B Problems
*2015**AMC 12B*Problems_数学_高中教育_教育专区。*2015**AMC 12B*Problems Problem...二级java考前押密*试题*文档贡献者 hognchen1999 贡献于*2015*-03-25 专题推荐 201...

- 2000到2015年AMC 10美国数学竞赛 1
- 2000到
*2015年AMC*10美国数学*竞赛*1_其它考试_资格...A. 正确 B. 错误单选题,请选择你认为正确的*答案*!...左侧 D. 前方判断题,请判断对错! 43、 载客汽车...

- 2015年六年级希望杯培训100题
*2015年*六年级希望杯培训100题_学科*竞赛*_小学教育_教育...(*答案*用最简分数表示) 52、 某风景区的介绍文字中...,使得四边形*AMC*N ? 的面积等于正方形 ABCD ...

- 2012天津市数学竞赛初赛试卷及答案
- 2012天津市数学
*竞赛*初赛*试卷及答案*_学科*竞赛*_初中教育...2MA?MC ? cos ?*AMC*, BD2 ? MB2 ? MD2 ?...文档贡献者 魅力依依8686 贡献于*2015*-09-09 相关...

- 2015 AMC 12A 美国数学竞赛 2015年 12A
- 2015
*AMC*12A 美国数学竞赛*2015年*12A_学科竞赛_初中教育_教育专区。American ...*AMC*美国数学*竞赛题*10页 免费 2005年美国数学竞赛-*AMC*... 8页 免费 2006...

- 全国初中数学竞赛试题及答案(1999年)
- 全国初中数学
*竞赛试题及答案*(1999年)。good中国数学教育网 http://www.mathedu...∵∠*AMC*=44°.又 AN 为切线,∴∠NAC=∠B =36°,∠NAM=44°,∴∠N=180...

更多相关标签:

- amc数学竞赛真题 | amc10 真题2016答案 | 2015 amc 12b 解析 | 2017amc12b | 2015amc12b | 2010amc12b | amc 12b | 2006年amc12b解答 |

- 2013年AMC12B竞赛真题及答案
- 2015年全国企业会计信息化知识竞赛(真题)及答案
- 2015年中小学生交通安全知识网络竞赛试卷真题及答案
- 2015年会计业务基础知识竞赛真题及答案
- 2015年银行电子银行业务知识竞赛真题及答案
- 2015年第二十五届全国初中应用物理竞赛真题
- 2015年消费者权益保护网络竞赛真题及答案
- 2015年安全生产月安全知识竞赛考题及答案
- 2015年新《安全生产法》知识竞赛综合试题及答案
- 2015年宁波市高中“语文报”杯阅读竞赛真题
- 2015年第二十五届全国初中应用物理竞赛与参考答案
- 2015年第二十五届全国初中应用物理竞赛试题
- 2014年第二十四届全国初中应用物理竞赛试题及答案
- 2015年全国初中数学联赛试题及答案
- 2015全国初中物理竞赛(巨人杯)试题及答案