olymmath

AMC 8 2011

AMC 8 2011.

Paper

Problem 2

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Karl's rectangular vegetable garden is 2020 feet by 4545 feet, and Makenna's is 2525 feet by 4040 feet. Whose garden is larger in area? (A) Karl’s garden is larger by 100 square feet.\textbf{(A)}\ \text{Karl's garden is larger by 100 square feet.} (B) Karl’s garden is larger by 25 square feet.\textbf{(B)}\ \text{Karl's garden is larger by 25 square feet.} (C) The gardens are the same size.\textbf{(C)}\ \text{The gardens are the same size.} (D) Makenna’s garden is larger by 25 square feet.\textbf{(D)}\ \text{Makenna's garden is larger by 25 square feet.} (E) Makenna’s garden is larger by 100 square feet.\textbf{(E)}\ \text{Makenna's garden is larger by 100 square feet.}

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Problem 3

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Extend the square pattern of 8 black and 17 white square tiles by attaching a border of black tiles around the square. What is the ratio of black tiles to white tiles in the extended pattern?

(A) 8:17(B) 25:49(C) 36:25(D) 32:17(E) 36:17\textbf{(A) }8:17 \textbf{(B) }25:49 \textbf{(C) }36:25 \textbf{(D) }32:17 \textbf{(E) }36:17

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Problem 4

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Here is a list of the numbers of fish that Tyler caught in nine outings last summer: 2,0,1,3,0,3,3,1,2.2,0,1,3,0,3,3,1,2. Which statement about the mean, median, and mode is true? (A) median<mean<mode(B) mean<mode<median(C) mean<median<mode(D) median<mode<mean(E) mode<median<mean\textbf{(A)}\ \text{median} < \text{mean} < \text{mode} \textbf{(B)}\ \text{mean} < \text{mode} < \text{median} \\ \\ \textbf{(C)}\ \text{mean} < \text{median} < \text{mode} \textbf{(D)}\ \text{median} < \text{mode} < \text{mean} \\ \\ \textbf{(E)}\ \text{mode} < \text{median} < \text{mean}

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Problem 5

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What time was it 20112011 minutes after midnight on January 1, 2011? (A) January 1 at 9:31PM\textbf{(A)}\ \text{January 1 at 9:31PM} (B) January 1 at 11:51PM\textbf{(B)}\ \text{January 1 at 11:51PM} (C) January 2 at 3:11AM\textbf{(C)}\ \text{January 2 at 3:11AM} (D) January 2 at 9:31AM\textbf{(D)}\ \text{January 2 at 9:31AM} (E) January 2 at 6:01PM\textbf{(E)}\ \text{January 2 at 6:01PM}

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Problem 6

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In a town of 351351 adults, every adult owns a car, motorcycle, or both. If 331331 adults own cars and 4545 adults own motorcycles, how many of the car owners do not own a motorcycle? (A) 20(B) 25(C) 45(D) 306(E) 351\textbf{(A)}\ 20 \textbf{(B)}\ 25 \textbf{(C)}\ 45 \textbf{(D)}\ 306 \textbf{(E)}\ 351

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Problem 7

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Each of the following four large congruent squares is subdivided into combinations of congruent triangles or rectangles and is partially bolded. What percent of the total area is partially bolded?

(A) 1212(B) 20(C) 25(D) 3313(E) 3712\textbf{(A) }12\frac{1}{2} \textbf{(B) }20 \textbf{(C) }25 \textbf{(D) }33\frac{1}{3} \textbf{(E) }37\frac{1}{2}

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Problem 8

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Bag A has three chips labeled 1, 3, and 5. Bag B has three chips labeled 2, 4, and 6. If one chip is drawn from each bag, how many different values are possible for the sum of the two numbers on the chips? (A) 4(B) 5(C) 6(D) 7(E) 9\textbf{(A) }4 \textbf{(B) }5 \textbf{(C) }6 \textbf{(D) }7 \textbf{(E) }9

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Problem 9

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Carmen takes a long bike ride on a hilly highway. The graph indicates the miles traveled during the time of her ride. What is Carmen's average speed for her entire ride in miles per hour?

(A)2(B)2.5(C)4(D)4.5(E)5\textbf{(A)}2 \textbf{(B)}2.5 \textbf{(C)}4 \textbf{(D)}4.5 \textbf{(E)}5

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Problem 10

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The taxi fare in Gotham City is 2.40forthefirst2.40 for the first\frac12mileandadditionalmileagechargedattheratemile and additional mileage charged at the rate0.20 for each additional 0.1 mile. You plan to give the driver a 2tip.Howmanymilescanyouridefor2 tip. How many miles can you ride for10? (A) 3.0(B) 3.25(C) 3.3(D) 3.5(E) 3.75\textbf{(A) }3.0 \textbf{(B) }3.25 \textbf{(C) }3.3 \textbf{(D) }3.5 \textbf{(E) }3.75

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Problem 11

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The graph shows the number of minutes studied by both Asha (black bar) and Sasha (grey bar) in one week. On the average, how many more minutes per day did Sasha study than Asha?

(A) 6(B) 8(C) 9(D) 10(E) 12\textbf{(A)}\ 6 \textbf{(B)}\ 8 \textbf{(C)}\ 9 \textbf{(D)}\ 10 \textbf{(E)}\ 12

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Problem 12

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Angie, Bridget, Carlos, and Diego are seated at random around a square table, one person to a side. What is the probability that Angie and Carlos are seated opposite each other? (A) 14(B) 13(C) 12(D) 23(E) 34\textbf{(A) } \frac14 \textbf{(B) } \frac13 \textbf{(C) } \frac12 \textbf{(D) } \frac23 \textbf{(E) } \frac34

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Problem 13

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Two congruent squares, ABCDABCD and PQRSPQRS, have side length 1515. They overlap to form the 1515 by 2525 rectangle AQRDAQRD shown. What percent of the area of rectangle AQRDAQRD is shaded?

(A) 15(B) 18(C) 20(D) 24(E) 25\textbf{(A)}\ 15 \textbf{(B)}\ 18 \textbf{(C)}\ 20 \textbf{(D)}\ 24 \textbf{(E)}\ 25

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Problem 14

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There are 270270 students at Colfax Middle School, where the ratio of boys to girls is 5:45 : 4. There are 180180 students at Winthrop Middle School, where the ratio of boys to girls is 4:54 : 5. The two schools hold a dance and all students from both schools attend. What fraction of the students at the dance are girls? (A) 718(B) 715(C) 2245(D) 12(E) 2345\textbf{(A) } \dfrac7{18} \textbf{(B) } \dfrac7{15} \textbf{(C) } \dfrac{22}{45} \textbf{(D) } \dfrac12 \textbf{(E) } \dfrac{23}{45}

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Problem 15

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How many digits are in the product 45⋅5104^5 \cdot 5^{10}? (A) 8(B) 9(C) 10(D) 11(E) 12\textbf{(A) } 8 \textbf{(B) } 9 \textbf{(C) } 10 \textbf{(D) } 11 \textbf{(E) } 12

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Problem 16

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Let AA be the area of the triangle with sides of length 25,2525, 25, and 3030. Let BB be the area of the triangle with sides of length 25,25,25, 25, and 4040. What is the relationship between AA and BB? (A) A=916B(B) A=34B(C) A=B(D) A=43B(E) A=169B\textbf{(A) } A = \dfrac9{16}B \textbf{(B) } A = \dfrac34B \textbf{(C) } A=B \textbf{(D) } A = \dfrac43B \textbf{(E) }A = \dfrac{16}9B

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Problem 17

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Let ww, xx, yy, and zz be whole numbers. If 2w⋅3x⋅5y⋅7z=5882^w \cdot 3^x \cdot 5^y \cdot 7^z = 588, then what does 2w+3x+5y+7z2w + 3x + 5y + 7z equal? (A) 21(B) 25(C) 27(D) 35(E) 56\textbf{(A) } 21 \textbf{(B) }25 \textbf{(C) }27 \textbf{(D) }35 \textbf{(E) }56

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Problem 18

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A fair 66 sided die is rolled twice. What is the probability that the first number that comes up is greater than or equal to the second number? (A) 16(B) 512(C) 12(D) 712(E) 56\textbf{(A) }\dfrac16 \textbf{(B) }\dfrac5{12} \textbf{(C) }\dfrac12 \textbf{(D) }\dfrac7{12} \textbf{(E) }\dfrac56

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Problem 19

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How many rectangles are in this figure?

(A) 8(B) 9(C) 10(D) 11(E) 12\textbf{(A)}\ 8 \textbf{(B)}\ 9 \textbf{(C)}\ 10 \textbf{(D)}\ 11 \textbf{(E)}\ 12

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Problem 20

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Quadrilateral ABCDABCD is a trapezoid, AD=15AD = 15, AB=50AB = 50, BC=20BC = 20, and the altitude is 1212. What is the area of the trapezoid?

(A) 600(B) 650(C) 700(D) 750(E) 800\textbf{(A) }600 \textbf{(B) }650 \textbf{(C) }700 \textbf{(D) }750 \textbf{(E) }800

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Problem 21

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Students guess that Norb's age is 24,28,30,32,36,38,41,44,4724, 28, 30, 32, 36, 38, 41, 44, 47, and 4949. Norb says, "At least half of you guessed too low, two of you are off by one, and my age is a prime number." How old is Norb? (A) 29(B) 31(C) 37(D) 43(E) 48\textbf{(A) }29 \textbf{(B) }31 \textbf{(C) }37 \textbf{(D) }43 \textbf{(E) }48

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Problem 22

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What is the tens digit of 720117^{2011}? (A) 0(B) 1(C) 3(D) 4(E) 7\textbf{(A) }0 \textbf{(B) }1 \textbf{(C) }3 \textbf{(D) }4 \textbf{(E) }7

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Problem 23

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How many 4-digit positive integers have four different digits, where the leading digit is not zero, the integer is a multiple of 5, and 5 is the largest digit? (A) 24(B) 48(C) 60(D) 84(E) 108\textbf{(A) }24 \textbf{(B) }48 \textbf{(C) }60 \textbf{(D) }84 \textbf{(E) }108

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Problem 24

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In how many ways can 1000110001 be written as the sum of two primes? (A) 0(B) 1(C) 2(D) 3(E) 4\textbf{(A) }0 \textbf{(B) }1 \textbf{(C) }2 \textbf{(D) }3 \textbf{(E) }4

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Problem 25

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A circle with radius 11 is inscribed in a square and circumscribed about another square as shown. Which fraction is closest to the ratio of the circle's shaded area to the area between the two squares?

(A) 12(B) 1(C) 32(D) 2(E) 52\textbf{(A)}\ \frac{1}2 \textbf{(B)}\ 1 \textbf{(C)}\ \frac{3}2 \textbf{(D)}\ 2 \textbf{(E)}\ \frac{5}2

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