2023 袋鼠数学 E-Junior 真题 答案 详解

中英双语真题

MATH KANGAROO CHINA Math Kangaroo 2023 (China)-Level E 3 points 1. A grey circle with two holes is put on top of a clock-face, as shown. 如图所示，将带有两个孔的灰色圆盘放在钟面上。 The grey circle is turned around the centre such that the number 10 appears in one hole. Which numbers is it possible to see in the other hole? 灰色圆盘绕其中心旋转，一个孔中出现数字10。另一个孔中可能看到哪些数字？ (A) 2 and 6 2和6 (B) 3 and 7 3和7 (C) 3 and 6 3和6 (D) 1 and 9 1和9 (E) 2 and 7 2和7 2. Maria had to run to catch the subway, got off two stops later and then walked to school. Which of the following speed-time graphs would best represent her journey? Maria 必须跑着去乘坐地铁，两站后下车，然后步行去学校。以下哪个速度和时间的关系图象最符合Maria 的行程？ (A) (B) (C) (D) (E) 3. The positive integers m and n are both odd. Which of the following integers is also odd? 正整数m 和n 都是奇数。下面哪个整数也是奇数？ (A) m(n+1) (B) (m+1)(n+1) (C) m+n+2 (D) m·n+2 (E) m+n 4. A large square of side-length 10 cm contains a smaller square of side-length 4 cm, as shown in the diagram. The corresponding sides of the two squares are parallel. What percentage of the large square is shaded? 边长为10 cm的大正方形内部有一个边长为4 cm的小正方形，如图所示。两个正方形相对应的边是平行的。阴影部分占大正方形的百分比是多少？ (A) 25% (B) 30% (C) 40% (D) 42% (E) 45% 3