2015 澳洲 AMC A-MiddlePrimary 真题 答案 详解

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中英双语真题

Elementary School Mid-Year Exam 1-10 questions, 3 points each
1. How many dots are there inside the circle on the right?
(A) 10 (B) 12 (C) 13 (D) 14 (E) 15

1. Xiaojie has 15 grapes. After eating 5, how many are left?
   (A) 7 (B) 8 (C) 9 (D) 10 (E) 11

2. Use the grid on the right to indicate the position of different patterns. For example, the diamond is at B4. What shape is at D2?
   (A) Diamond (B) Cross (C) Heart (D) Circle (E) Triangle

3. What fraction of the square on the right is shaded?
   (A) ( \frac{1}{2} ) (B) ( \frac{1}{3} ) (C) ( \frac{1}{4} ) (D) ( \frac{1}{5} ) (E) ( \frac{1}{6} )

4. On the circular spinner shown on the right, which pattern has a higher chance of being landed on?
   (A) Triangle (B) Square (C) Star (D) Spade (E) Dot

英文真题

Middle Primary Division
Questions 1 to 10, 3 marks each

1. How many dots are on the plate?
   (A) 10
   (B) 12
   (C) 13
   (D) 14
   (E) 15

2. Jill had 15 grapes. She ate 5. How many are left?
   (A) 7
   (B) 8
   (C) 9
   (D) 10
   (E) 11

3. This grid gives the position of different shapes. For example, a ▲ is in position B4. Which shape is in position D2?
   (A) ◇
   (B) ⊕
   (C) ♥
   (D) ●
   (E) △

4. What fraction of this shape is shaded?
   (A) ( \frac{1}{2} )
   (B) ( \frac{1}{3} )
   (C) ( \frac{1}{4} )
   (D) ( \frac{1}{5} )
   (E) ( \frac{1}{6} )

真题文字详解(英文)

Solutions – Middle Primary Division
1. 5 groups of 3, so 5 × 3 = 15, hence (E).
2. 15 - 5 = 10, hence (D).
3. In the bottom row (labelled D) and the second column (labelled 2) the shape is ♥, hence (C).
4. Of the 4 equal parts, 1 is shaded, so the fraction is ( \frac{1}{4} ), hence (C).
5. In the 6 equal spaces the shape • appears twice, so it is more likely, while all other shapes appear only once, hence (E).
6. It is after 12, and the minute hand is one-quarter of a turn from '12' so the time is a quarter past twelve, hence (D).
7. 6 + 7 + 3 + 5 = 21, hence (C).
8. (Also UP4) Increasing the 19 to 20 requires that we decrease the 45 to 44, hence (B).
9. The area of the large rectangle is 56 units, while the area of the small rectangle is 2 units, so the number of rectangles is ( \frac{56}{2} = 28 ). These rectangles can be placed in 7 rows of 4, hence (B).
10. Ethan took the least time, so he won, hence (B).
11. Each group of beads in the pattern has two round beads, so the 18th round bead will be in the 9th group. However, the last group won't have a square bead, so there are only 8 square beads, hence (E).

2015 AMC – Middle Primary Solutions