2009 AMC amc8 真题 答案 详解

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中英双语真题

2009 AMC8
Problem 1
Bridget bought a bag of apples at the grocery store. She gave half of the apples to Ann. Then she gave Cassie 3 apples, keeping 4 apples for herself. How many apples did Bridget buy?
Bridget 在水果店买了一包苹果。她把一半苹果给了 Ann，然后她把 3 个苹果了 Cassie，自己留了 4 个。那么 Bridget 总共买了多少个苹果？
(A) 3 (B) 4 (C) 7 (D) 11 (E) 14

Problem 2
On average, for every 4 sports cars sold at the local dealership, 7 sedans are sold. The dealership predicts that it will sell 28 sports cars next month. How many sedans does it expect to sell?
平均下来，当地经销商每售出 4 辆跑车，就售出 7 辆轿车。该经销商预计下个月将销售 28 辆跑车，那么预计销售多少辆轿车？
(A) 7 (B) 32 (C) 35 (D) 49 (E) 112

Problem 3
The graph shows the constant rate at which Suzanna rides her bike. If she rides a total of a half an hour at the same speed, how many miles would she have ridden?
下图显示了 Suzanna 以恒定的速度骑自行车。如果她以同样的速度骑了半个小时，她将骑多少英里？
(A) 5 (B) 5.5 (C) 6 (D) 6.5 (E) 7

英文真题

Compiled on: January 1, 2021 AMC8 2009 Problems Page 52 of 109 Q1. Bridget bought a bag of apples at the grocery store. She gave half of the apples to Ann. Then she gave Cassie 3 apples, keeping 4 apples for herself. How many apples did Bridget buy? A) 3 B) 4 C) 7 D) 11 E) 14 Q2. On average, for every 4 sports cars sold at the local dealership, 7 sedans are sold. The dealership predicts that it will sell 28 sports cars next month. How many sedans does it expect to sell? A) 7 B) 32 C) 35 D) 49 E) 112 Q3. The graph shows the constant rate at which Suzanna rides her bike. If she rides a total of a half an hour at the same speed, how many miles would she have ridden? A) 5 B) 5.5 C) 6 D) 6.5 E) 7 Q4. The five pieces shown below can be arranged to form four of the five figures shown in the choices. Which figure cannot be formed? Q5. A sequence of numbers starts with 1, 2, and 3. The fourth number of the sequence is the sum of the previous three numbers: 1 + 2 + 3 = 6. In the same way, every number after the fourth is the sum of the previous three numbers. What is the eighth number in the sequence? A) 11 B) 20 C) 37 D) 68 E) 99 Q6. Steve's empty swimming pool will hold 24,000 gallons of water when full. It will be filled by 4 hoses, each of which supplies 2.5 gallons of water per minute. How many hours will it take to fill Steve’s pool? A) 40 B) 42 C) 44 D) 46 E) 48 Q7. The triangular plot of ACD lies between Aspen Road, Brown Road and a railroad. Main Street runs east and west, and the railroad runs north and south. The numbers in the diagram indicate distances in miles. The width of the railroad track can be ignored. How many square miles are in the plot of land ACD?

真题文字详解(英文)

Problem 1

Bridget bought a bag of apples at the grocery store. She gave half of the apples to Ann. Then she gave Cassie 3 apples, keeping 4 apples for herself. How many apples did Bridget buy?

[ \begin{array}{ll} \text{(A)} & 3 \ \text{(B)} & 4 \ \text{(C)} & 7 \ \text{(D)} & 11 \ \text{(E)} & 14 \ \end{array} ]

Solution

If we set up an equation, we find out ( x = (3 + 4) \cdot 2 ) because 3 apples were left after giving half, then four away. We can simplify the equations to ( x = 7 \cdot 2 = 14 ). The answer is (E) 14.

Solution 2

You can work backwards and add 3 apples that she gave to Cassie to the 4 she currently has, which results in 7, and then multiply by 2 since she gave half the apples to Ann, resulting in (E) 14. ~Anabel.disher

Problem 2

On average, for every 4 sports cars sold at the local dealership, 7 sedans are sold. The dealership predicts that it will sell 28 sports cars next month. How many sedans does it expect to sell?

[ \begin{array}{ll} \text{(A)} & 7 \ \text{(B)} & 32 \ \text{(C)} & 35 \ \text{(D)} & 49 \ \text{(E)} & 112 \ \end{array} ]

Solution

This means the ratio is ( 4 : 7 ). If the ratio now is ( 28 : x ), then that means ( x = \boxed{\text{(D)} 49} ).

Problem 3

The graph shows the constant rate at which Suzanna rides her bike. If she rides a total of a half an hour at the same speed, how many miles would she have ridden?

真题文字详解(中英双语)

Problem 1 Bridget bought a bag of apples at the grocery store. She gave half of the apples to Ann. Then she gave Cassie 3 apples, keeping 4 apples for herself. How many apples did Bridget buy? (A) 3 (B) 4 (C) 7 (D) 11 (E) 14 Solution If we set up an equation, we find out x = (3 + 4) · 2 because 3 apples were left after giving half, then four away. We can simplify the equations to x = 7 · 2 = 14. The answer is (E) 14. 如果我们列出一个方程，我们会发现 x = (3 + 4) · 2 ，因为她在给了一半之后还剩下 3 个苹果，然后又给了 4 个。我们可以简化这个方程到 x = 7 · 2 = 14. 答案是 (E) 14. Solution 2 You can work backwards and add 3 apples that she gave to Cassie to the 4 she currently has, which results in 7, and then multiply by 2 since she gave half the apples to Ann, resulting in (E) 14. ~Anabel.disher 你可以倒推，把给凯西的 3 个苹果加到她目前有的 4 个苹果上，结果是 7 个，然后乘以 2 ，因为她给安了一半的苹果，结果是 (E) 14 。~Anabel.disher Problem 2 On average, for every 4 sports cars sold at the local dealership, 7 sedans are sold. The dealership predicts that it will sell 28 sports cars next month. How many sedans does it expect to sell? (A) 7 (B) 32 (C) 35 (D) 49 (E) 112 Solution This means the ratio is 4 : 7. If the ratio now is 28 : x, then that means x = (D) 49. 这意味着比率是 4 : 7。如果比率现在是 28 : x，那么这意味着 x = (D) 49. Problem 3 The graph shows the constant rate at which Suzanna rides her bike. If she rides a total of a half an hour at the same speed, how many miles would she have ridden? 图表显示了苏珊娜骑自行车的恒定速度。如果她以同样的速度骑了半小时，她会骑多少英里？