2009 袋鼠数学 D-Cadet 真题 答案 详解

英文真题

International Kangaroo Mathematics Contest 2009 - Cadet 1 Cadet Level: Class (7 & 8) Max Time: 2 Hours 3-Point Problems 1. Among these numbers, which is even? (A) 2009 (B) 201019 (C) 2009 (D) 200×9 2. At a competition there were 4 boys and 4 girls. Boys compete only with girls and girls compete only with boys. Afterwards we asked all of them, how many competitions they each had. The boys said: 3, 1, 2, 2. Three of girls said: 2, 2, 2. What number did the fourth girl say? (A) 0 (B) 1 (C) 2 (D) 3 3. The star in the picture is formed from 12 identical small equilateral triangles. The perimeter of the star is 36 cm. What is the perimeter of the dark hexagon? (A) 6 cm (B) 12 cm (C) 18 cm (D) 24 cm 4. Harry delivers folders in Long Street. He must deliver a folder to all the houses with an odd number. The first house has number 15, the last one has number 53. How many houses does Harry deliver to? (A) 19 (B) 20 (C) 27 (D) 38 5. The area of the big square is 1. What is the area of the black little square? (A) \frac{1}{300} (B) \frac{1}{600} (C) \frac{1}{900} (D) \frac{1}{1000} 6. The product of four different positive integers is 100. What is their sum? (A) 10 (B) 12 (C) 15 (D) 18 7. There are cats and dogs in the room. The number of the cats' paws is twice the number of the dogs' noses. Then the number of cats is (A) twice the number of dogs (B) equal to the number of dogs (C) half the number of dogs (D) \frac{1}{4} of the number of dogs