2012 澳洲 AMC C-Junior 真题 答案 详解

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中英双语真题

Primary level (7-8 grade)

1-10 questions, 3 points each

1. Calculate 99 - 2 + 1 + 102 equals: (A) 0 (B) 100 (C) 198 (D) 200 (E) 202

2. In the diagram below, what is the measure of ∠Q? (A) 40 (B) 55 (C) 60 (D) 80 (E) 90

3. The rain started at 9:45 am yesterday and ended at 3:10 pm the same day. How long did the rain last? (A) 3 hours 25 minutes (B) 3 hours 35 minutes (C) 5 hours 25 minutes (D) 6 hours 25 minutes (E) 6 hours 35 minutes

4. Calculate 8 × 3.1 equals: (A) 11.1 (B) 16.8 (C) 8.31 (D) 24.1 (E) 24.8

5. If you pay $20 for a bill of $9.45, how much change should you receive? (A) $10.55 (B) $10.45 (C) $11.55 (D) $9.55 (E) $10.65

6. A number's three-fifths is 48. What is that number? (A) 54 (B) 60 (C) 64 (D) 80 (E) 84

7. Which of the following values is closest to 100? (A) 99 + 2.01 (B) 98 + 3.011 (C) 97 + 4.0111 (D) 101 - 1.01 (E) 102 - 2.011

英文真题

Junior Division
Questions 1 to 10, 3 marks each

1. The value of (99 - 2 + 1 + 102) is
   (A) 0
   (B) 100
   (C) 198
   (D) 200
   (E) 202

2. The size, in degrees, of (\angle Q) is
   (A) 40
   (B) 55
   (C) 60
   (D) 80
   (E) 90

3. Yesterday it rained continuously from 9:45 am until 3:10 pm. For how long did it rain?
   (A) 3 hours 25 minutes
   (B) 3 hours 35 minutes
   (C) 5 hours 25 minutes
   (D) 6 hours 25 minutes
   (E) 6 hours 35 minutes

4. The value of (8 \times 3.1) is
   (A) 11.1
   (B) 16.8
   (C) 8.31
   (D) 24.1
   (E) 24.8

5. The change you should receive from a $20 note after paying a bill of $9.45 is
   (A) $10.55
   (B) $10.45
   (C) $11.55
   (D) $9.55
   (E) $10.65

6. Three-fifths of a number is 48. What is the number?
   (A) 54
   (B) 60
   (C) 64
   (D) 80
   (E) 84

7. Which of the following is closest to 100?
   (A) (99 + 2.01)
   (B) (98 + 3.011)
   (C) (97 + 4.0111)
   (D) (101 - 1.01)
   (E) (102 - 2.011)

真题文字详解(英文)

SOLUTIONS - JUNIOR DIVISION 1. 99-2+1+102=200, hence (D). 2. As the angle sum of the triangle is 180°, ∠PQR = 180°-45°-55° = 80°, hence (D). 3. From 9:45 am to 3:10 pm is 5 hours and 15 + 10 = 25 minutes, hence (C). 4. 8 × 3.1 = 24.8, hence (E). 5. $20-$9.45=$10.55, hence (A). 6. (Also I4) Alternative 1 We have \frac{3x}{5} = 48, so 3x = 5 × 48 and x = 5 × 16 = 80, hence (D). Alternative 2 Three-fifths of the number is 48, so one-fifth of the number is 48 ÷ 3 = 16 and the number is 5 × 16 = 80, hence (D). 7. (A) is 99+2.01=101.01, (B) is 98+3.011=101.011, (C) is 97+4.0111=101.0111, (D) is 101-1.01=99.99 and (E) is 102-2.011=99.989, hence (D). 32