2008 AMC10美国数学竞赛A卷
1. A bakery owner turns on his doughnut machine at8:30 AM. At 11:10 AM the machine has completed one third of the day’s job. At what time will the doughnut machine complete the job?
(A) 1:50 PM (B) 3:00 PM (C) 3:30 PM (D) 4:30 PM (E) 5:50 PM
2. A square is drawn inside a rectangle. The ratio of the width of the rectangle to a side of the square is 2:1. The ratio of the rectangle’s length to its width is 2:1. What percent of the rectangle’s area is inside the square?
(A) 12.5 (B) 25 (C) 50 (D) 75 (E) 87.5
3. For the positive integer n, let <n> denote the sum of all the positive divisors of n with the exception of n itlf. For example, <4>=1+2=3 and <12>=1+2+3+4+6=16. What is <<<6>>>?
(A) 6 (B) 12 (C) 24 (D) 32 (E) 36
4. Suppo that 2/3 of 10 bananas are worth as much as 8 oranges. How many oranges are worth as much as 1/2 of 5 bananas?
(A) 2 (B) 5/2 (C) 3 (D) 7/2 (E) 4contactus
5. Which of the following is equal to the product
(A) 251 (B) 502 (C) 1004 (D) 2008 (E) 4016
6. A triathlete competes in a triathlon in which the swimming, biking, and running gments are all of the same length. The triathlete swims at a rate of 20 kilometers per hour, and runs at a rate of 10 kilometers per hour. Which of the following is clost to the triathlete’s average speed, in kilometers per hour, for the entire race?
(A) 3 (B) 4 (C) 5 (D) 6 (E) 7
7. The fraction simplifies to which of the following?
紫色配什么色好看
(A) 1 (B) 9/4 (C) 3 (D) 9/2 (E) 9
8. Heather compares the price of a new computer at two different stores. Store A offers 15% off the sticker price followed by a $90 rebate, and store B offers 25% off the same sticker price with no rebate. Heather saves $15 by buying the computer at store A instead of store B. What is the sticker price of the computer, in dollars?
(A) 750 (B) 900 (C) 1000 (D) 1050 (E) 1500
职业生涯规划书ppt9.Suppo that is an integer. Which of the following statements must be true about x?
(A) It is negative.
(B) It is even, but not necessarily a multiple of 3.
(C) It is multiple of 3, but not necessarily even.
(D) It is a multiple of 6, but not necessarily a multiple of 12.
(E) It is a multiple of 12.
10. Each of the sides of a square s with area 16 is bicted, and a smaller square s is constructed using the biction points as vertices. The same process is carried out on s to construct an even smaller square s. What is the area of s?
英汉字典>六级翻译(A) 1/2 (B) 1 (C) 2 (D) 3 (E) 4
11. While Steve and LeRoy are fishing 1 mile from shore, their boat springs a leak, and water comes in at a constant rate of 10 gallons per minute. The boat will sink if it takes in more than 30 gallons of water. Steve starts rowing toward the shore at a constant rate of 4 miles per hour while LeRoy bails water out of the boat. What is the slowest rate, in gallons per minute, at which LeRoy can bail if they are to reach the shore without sinking?
(A) 2 (B) 4 (C) 6 (D) 8 (E) 10
12. In a collection of red, blue, and green marbles, there are 25% more red marbles than
blue marbles, and there are 60% more green marbles than red marbles. Suppo that there are r red marbles. What is the total number of marbles in the collection?
translate google(A) 2.85r (B) 3r (C) 3.4r (D) 3.85r (E) 4.25r复古风英文
13. Doug can paint a room in 5 hours. Dave can paint the same room in 7 hours. Doug and Dave paint the room together and take a one-hour break for lunch. Let t be the total time, in hours, required for them to complete the job working together, including lunch. Which of the following equations is satisfied by t?
(A) (B) (C)
(D) (E)
14. Older television screens have an aspect ratio of 4:3. That is , the ratio of the width to the height is 4:3. The aspect ratio of many movies is not 4:3, so they are sometimes shown on a television screen by “letterboxing”- darkening strips of equal height at the top and bottom of the screen, as shown. Suppo a movie has an aspect ratio of 2:1 and is shown on an older television screen with a 27-inch diagonal. What is the height, in inches, of each darkened strip?
(A) 2 (B) 2.25 (C) 2.5 (D) 2.7 (E) 3
15. Yesterday Han drove 1 hour longer than Ian at an average speed 5 miles per hour faster than Ian. Jan drove 2 hours longer than Ian at an average speed 10 miles per hour faster than Ian. Han drove 70 miles more than Ian. How many more miles did Jan drive than Ian?
(A) 120 (B) 130 (C) 140 (D) 150 (E) 160号外是什么意思
16. Points A and B lie on a circle centered at O, and ∠AOB=60°. A cond circle is internally tangent to the first and tangent to both OA and OB. What is the ratio of the area of the smaller circle to that the larger circle?
(A) 1/16 (B) 1/9 (C) 1/8 (D) 1/6 (E) 1/4
17. An equilateral triangle has side length 6. What is the area of the region containing all points that are outside the triangle but not more than 3 units from a point of the triangle?
(A) (B) (C) 会计舞弊
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