『艾蕾特教育』AMC8 -- 2006年真题解析( 二 )


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Answer: D
Solution:
If Cassie leaves half an hour earlier then Brian, when Brian starts, the distance between them will be 62-12/2=56. Every hour, they will get 12+16=28 miles closer. 56/28=2, so 2 hours from 9:00 AM is when they meet, which is 11:00.
『艾蕾特教育』AMC8 -- 2006年真题解析
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Problem 14『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: B
Solution:
760*45-760*30=760*15=11400.Problem 15
『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: C
Solution:
we set up an equation and solve.Let x be the number of pages that Chandra reads. 30*x=45*(760-x), thus x=456.Problem 16
『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: E
Solution:
The amount of pages Bob, Chandra, and Alice will read is in the ratio 4:6:9. Therefore, Bob, Chandra, and Alice read 160, 240, and 360 pages respectively. They would also be reading for the same amount of time because the ratio of the pages read was based on the time it takes each of them to read a page. Therefore, the amount of seconds each person reads is simply 160*45=7200.Problem 17
『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: B
Solution:
In order for Jeff to have an odd number sum, the numbers must either be Odd + Odd + Odd or Even + Even + Odd. We easily notice that we cannot obtain Odd + Odd + Odd because spinner Q contains only even numbers. Therefore we must work with Even + Even + Odd and spinner Q will give us one of our even numbers. We also see that spinner R only contains odd, so spinner R must give us our odd number. We still need one even number from spinner P. There is only 1 even number: 2. Since spinning the required numbers are automatic on the other spinners, we only have to find the probability of spinning a 2 in spinner P, which is clearly 1/3.Problem 18
『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: D
Solution:
The surface area of the cube is 6*3*3=54. Each of the eight black cubes has 3 faces on the outside, making 3*8=24 black faces. Therefore there are 54-24=30 white faces. To find the ratio, we evaluate 30/54=5/9.Problem 19『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: D
Solution:
Since triangle ABD is congruent to triangle ECD and CE=11, AB=11. Since AB=BC, BC=11. Because point D is the midpoint of BC, BD=11/2=5.5.Problem 20
『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: C
Solution:
Since there are 6 players, a total of 6*5/2=15 games are played. So far, 4+3+2+2+2=13 games finished (one person won from each game), so Monica needs to win 15-13=2.Problem 21『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: A
Solution:
The water level will rise 1cm for every 100*40=4,000 . Since 1,000 is 1/4 of 4,000, the water will rise 1/4=0.25.Problem 22
『艾蕾特教育』AMC8 -- 2006年真题解析
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『艾蕾特教育』AMC8 -- 2006年真题解析
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Answer: D
Solution:
If the lower cells contain A,B, and C, then the second row will contain A+B and B+C , and the top cell will contain A+2B+C. To obtain the smallest sum, place 1 in the center cell and 2 and 3 in the outer ones. The top number will be 7. For the largest sum, place 9 in the center cell and 7 and 8 in the outer ones. This top number will be 33. The difference is 33-7=26.Problem 23
『艾蕾特教育』AMC8 -- 2006年真题解析


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