olymmath

AMC 8 1987

AMC 8 1987.

Paper

Problem 1

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.4+.02+.006=.4+.02+.006= (A) .012(B) .066(C) .12(D) .24(E).426\text{(A)}\ .012 \text{(B)}\ .066 \text{(C)}\ .12 \text{(D)}\ .24 \text{(E)} .426

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Problem 2

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225=\frac{2}{25}= (A) .008(B) .08(C) .8(D) 1.25(E) 12.5\text{(A)}\ .008 \text{(B)}\ .08 \text{(C)}\ .8 \text{(D)}\ 1.25 \text{(E)}\ 12.5

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Problem 3

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2(81+83+85+87+89+91+93+95+97+99)=2(81+83+85+87+89+91+93+95+97+99)= (A) 1600(B) 1650(C) 1700(D) 1750(E) 1800\text{(A)}\ 1600 \text{(B)}\ 1650 \text{(C)}\ 1700 \text{(D)}\ 1750 \text{(E)}\ 1800

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Problem 4

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Martians measure angles in clerts. There are 500500 clerts in a full circle. How many clerts are there in a right angle? (A) 90(B) 100(C) 125(D) 180(E) 250\text{(A)}\ 90 \text{(B)}\ 100 \text{(C)}\ 125 \text{(D)}\ 180 \text{(E)}\ 250

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Problem 5

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The area of the rectangular region is

(A) .088 m2(B) .62 m2(C) .88 m2(D) 1.24 m2(E) 4.22 m2\text{(A)}\ \text{.088 m}^2 \text{(B)}\ \text{.62 m}^2 \text{(C)}\ \text{.88 m}^2 \text{(D)}\ \text{1.24 m}^2 \text{(E)}\ \text{4.22 m}^2

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Problem 6

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The smallest product one could obtain by multiplying two numbers in the set {−7,−5,−1,1,3}\{ -7,-5,-1,1,3 \} is (A) −35(B) −21(C) −15(D) −1(E) 3\text{(A)}\ -35 \text{(B)}\ -21 \text{(C)}\ -15 \text{(D)}\ -1 \text{(E)}\ 3

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Problem 7

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The large cube shown is made up of 2727 identical sized smaller cubes. For each face of the large cube, the opposite face is shaded the same way. The total number of smaller cubes that must have at least one face shaded is (A) 10(B) 16(C) 20(D) 22(E) 24\text{(A)}\ 10 \text{(B)}\ 16 \text{(C)}\ 20 \text{(D)}\ 22 \text{(E)}\ 24

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Problem 9

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When finding the sum 12+13+14+15+16+17\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+\frac{1}{7}, the least common denominator used is (A) 120(B) 210(C) 420(D) 840(E) 5040\text{(A)}\ 120 \text{(B)}\ 210 \text{(C)}\ 420 \text{(D)}\ 840 \text{(E)}\ 5040

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Problem 10

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4(299)+3(299)+2(299)+298=4(299)+3(299)+2(299)+298= (A) 2889(B) 2989(C) 2991(D) 2999(E) 3009\text{(A)}\ 2889 \text{(B)}\ 2989 \text{(C)}\ 2991 \text{(D)}\ 2999 \text{(E)}\ 3009

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Problem 11

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The sum 217+312+51192\frac17+3\frac12+5\frac{1}{19} is between (A) 10 and 1012(B) 1012 and 11(C) 11 and 1112(D) 1112 and 12(E) 12 and 1212\text{(A)}\ 10\text{ and }10\frac12 \text{(B)}\ 10\frac12 \text{ and } 11 \text{(C)}\ 11\text{ and }11\frac12 \text{(D)}\ 11\frac12 \text{ and }12 \text{(E)}\ 12\text{ and }12\frac12

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Problem 12

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What fraction of the large 1212 by 1818 rectangular region is shaded?

(A) 1108(B) 118(C) 112(D) 29(E) 13\text{(A)}\ \frac{1}{108} \text{(B)}\ \frac{1}{18} \text{(C)}\ \frac{1}{12} \text{(D)}\ \frac29 \text{(E)}\ \frac13

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Problem 13

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Which of the following fractions has the largest value? (A) 37(B) 49(C) 1735(D) 100201(E) 151301\text{(A)}\ \frac{3}{7} \text{(B)}\ \frac{4}{9} \text{(C)}\ \frac{17}{35} \text{(D)}\ \frac{100}{201} \text{(E)}\ \frac{151}{301}

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Problem 14

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A computer can do 10,00010,000 additions per second. How many additions can it do in one hour? (A) 6 million(B) 36 million(C) 60 million(D) 216 million(E) 360 million\text{(A)}\ 6\text{ million} \text{(B)}\ 36\text{ million} \text{(C)}\ 60\text{ million} \text{(D)}\ 216\text{ million} \text{(E)}\ 360\text{ million}

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Problem 15

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The sale ad read: "Buy three tires at the regular price and get the fourth tire for 3 dollars." Sam paid 240 dollars for a set of four tires at the sale. What was the regular price of one tire? (A) 59.25 dollars(B) 60 dollars(C) 70 dollars(D) 79 dollars(E) 80 dollars\text{(A)}\ 59.25\text{ dollars} \text{(B)}\ 60\text{ dollars} \text{(C)}\ 70\text{ dollars} \text{(D)}\ 79\text{ dollars} \text{(E)}\ 80\text{ dollars}

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Problem 16

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Joyce made 1212 of her first 3030 shots in the first three games of this basketball game, so her seasonal shooting average was 40%40\%. In her next game, she took 1010 shots and raised her seasonal shooting average to 50%50\%. How many of these 1010 shots did she make? (A) 2(B) 3(C) 5(D) 6(E) 8\text{(A)}\ 2 \text{(B)}\ 3 \text{(C)}\ 5 \text{(D)}\ 6 \text{(E)}\ 8

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Problem 17

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Abby, Bret, Carl, and Dana are seated in a row of four seats numbered #1 to #4. Joe looks at them and says:

"Bret is next to Carl." "Abby is between Bret and Carl."

However each one of Joe's statements is false. Bret is actually sitting in seat #3. Who is sitting in seat #2? (A) Abby(B) Bret(C) Carl(D) Dana(E) There is not enough information to be sure.\text{(A)}\ \text{Abby} \text{(B)}\ \text{Bret} \text{(C)}\ \text{Carl} \text{(D)}\ \text{Dana} \text{(E)}\ \text{There is not enough information to be sure.}

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Problem 18

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Half the people in a room left. One third of those remaining started to dance. There were then 1212 people who were not dancing. The original number of people in the room was (A) 24(B) 30(C) 36(D) 42(E) 72\text{(A)}\ 24 \text{(B)}\ 30 \text{(C)}\ 36 \text{(D)}\ 42 \text{(E)}\ 72

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Problem 19

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A calculator has a squaring key x2\boxed{x^2} which replaces the current number displayed with its square. For example, if the display is 000003\boxed{000003} and the x2\boxed{x^2} key is depressed, then the display becomes 000009\boxed{000009}. If the display reads 000002\boxed{000002}, how many times must you depress the x2\boxed{x^2} key to produce a displayed number greater than 500500? (A) 4(B) 5(C) 8(D) 9(E) 250\text{(A)}\ 4 \text{(B)}\ 5 \text{(C)}\ 8 \text{(D)}\ 9 \text{(E)}\ 250

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Problem 20

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"If a whole number nn is not prime, then the whole number n−2n-2 is not prime." A value of nn which shows this statement to be false is (A) 9(B) 12(C) 13(D) 16(E) 23\textbf{(A)}\ 9 \textbf{(B)}\ 12 \textbf{(C)}\ 13 \textbf{(D)}\ 16 \textbf{(E)}\ 23

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Problem 21

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Suppose n∗n^{*} means 1n\frac{1}{n}, the reciprocal of nn. For example, 5∗=155^{*}=\frac{1}{5}. How many of the following statements are true?

i) 3∗+6∗=9∗3^*+6^*=9^* ii) 6∗−4∗=2∗6^*-4^*=2^* iii) 2∗⋅6∗=12∗2^*\cdot 6^*=12^* iv) 10∗÷2∗=5∗10^*\div 2^* =5^*

(A) 0(B) 1(C) 2(D) 3(E) 4\text{(A)}\ 0 \text{(B)}\ 1 \text{(C)}\ 2 \text{(D)}\ 3 \text{(E)}\ 4

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Problem 22

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ABCD\text{ABCD} is a rectangle, D\text{D} is the center of the circle, and B\text{B} is on the circle. If AD=4\text{AD}=4 and CD=3\text{CD}=3, then the area of the shaded region is between

(A) 4 and 5(B) 5 and 6(C) 6 and 7(D) 7 and 8(E) 8 and 9\text{(A)}\ 4\text{ and }5 \text{(B)}\ 5\text{ and }6 \text{(C)}\ 6\text{ and }7 \text{(D)}\ 7\text{ and }8 \text{(E)}\ 8\text{ and }9

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Problem 24

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A multiple choice examination consists of 2020 questions. The scoring is +5+5 for each correct answer, −2-2 for each incorrect answer, and 00 for each unanswered question. John's score on the examination is 4848. What is the maximum number of questions he could have answered correctly? (A) 9(B) 10(C) 11(D) 12(E) 16\text{(A)}\ 9 \text{(B)}\ 10 \text{(C)}\ 11 \text{(D)}\ 12 \text{(E)}\ 16

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Problem 25

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Ten balls numbered 11 to 1010 are in a jar. Jack reaches into the jar and randomly removes one of the balls. Then Jill reaches into the jar and randomly removes a different ball. The probability that the sum of the two numbers on the balls removed is even is (A) 49(B) 919(C) 12(D) 1019(E) 59\text{(A)}\ \frac{4}{9} \text{(B)}\ \frac{9}{19} \text{(C)}\ \frac{1}{2} \text{(D)}\ \frac{10}{19} \text{(E)}\ \frac{5}{9}

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