2020 澳洲 AMC C-Junior 真题 答案 详解

中英双语真题

2020 Australian Mathematics Competition — Junior 1-10 题，每题3分 Questions 1 to 10, 3 marks each 1. 请问右图中总共有多少个1×1的正方形？ How many 1 × 1 squares are in this diagram? (A) 16 (B) 18 (C) 20 (D) 24 (E) 25 2.请问2020的一半是多少？ What is half of 2020? (A) 20 (B) 101 (C) 110 (D) 1001 (E) 1010 3.请问右图三角形的周长是多少？ What is the perimeter of this triangle? (A) 33 m (B) 34 m (C) 35 m (D) 36 m (E) 37 m 4. 我在上午8:48搭上一列火车，并于上午9:21下车。请问我在这列火车上待了多少分钟？ I stepped on the train at 8.48 am and got off at 9.21 am. How many minutes did I spend on the train? (A) 27 (B) 33 (C) 43 (D) 87 (E) 93 5. 在这个三角形中，请问y的值是多少？ What is the value of y in this triangle? (A) 10 (B) 30 (C) 50 (D) 70 (E) 90 6. 2 - (0 - (2 - 0)) = (A) -4 (B) -2 (C) 0 (D) 2 (E) 4 7. 如右图，在方格表中，每一行的数字之和标在该行的最右边、每一列的数字之和标在该列的最下边。请问N的值是多少？ In the grid, the total of each row is given at the end of the row, and the total of each column is given at the bottom of the column. The value of N is (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

英文真题

Junior Division
Questions 1 to 10, 3 marks each

1. How many (1 \times 1) squares are in this diagram?
   (A) 16
   (B) 18
   (C) 20
   (D) 24
   (E) 25

2. What is half of 2020?
   (A) 20
   (B) 101
   (C) 110
   (D) 1001
   (E) 1010

3. What is the perimeter of this triangle?
   (A) 33 m
   (B) 34 m
   (C) 35 m
   (D) 36 m
   (E) 37 m

4. I stepped on the train at 8:48 am and got off at 9:21 am. How many minutes did I spend on the train?
   (A) 27
   (B) 33
   (C) 43
   (D) 87
   (E) 93

5. What is the value of (y) in this triangle?
   (A) 10
   (B) 30
   (C) 50
   (D) 70
   (E) 90

6. (2 - (0 - (2 - 0)) =)
   (A) -4
   (B) -2
   (C) 0
   (D) 2
   (E) 4

7. In the grid, the total of each row is given at the end of the row, and the total of each column is given at the bottom of the column. The value of (N) is
   (A) 1
   (B) 2
   (C) 3
   (D) 4
   (E) 5

真题文字详解(英文)

52 2020 AMC Junior Solutions Junior Solutions 1. The number of squares is 2 + 2 + 4 + 4 + 6 + 6 = 24, hence (D). 2. (Also UP2) 2020 ÷ 2 = 1010, hence (E). 3. (Also MP7, UP3) The perimeter is the sum of the three sides: 11 + 7 + 16 = 34 metres, hence (B). 4. There are 12 minutes from 8:48 am to 9 am and 21 minutes from 9 am to 9:21 am, a total of 12 + 21 = 33 minutes, hence (B). 5. The three angles in a triangle add to 180°. So 150 + y = 180 and y = 30, hence (B). 6. (Also I1) 2 - (0 - (2 - 0)) = 2 - (0 - 2) = 2 - (-2) = 2 + 2 = 4, hence (E). 7. (Also UP12) Using the totals around the sides, the 4 blank squares can be filled in. Then N = 1, hence (A). www.amt.edu.au