AMC8 1999

AMC8 1999 · Q20

AMC8 1999 · Q20. It mainly tests 3D geometry (volume), Logic puzzles.

Figure 1 is called a "stack map." The numbers tell how many cubes are stacked in each position. Fig. 2 shows these cubes, and Fig. 3 shows the view of the stacked cubes as seen from the front. Which of the following is the front view for the stack map in Fig. 4?

图 1 称为“堆叠图”。数字表示每个位置堆叠的立方体数量。图 2 显示这些立方体，图 3 显示从前面看到的堆叠立方体的视图。以下哪项是图 4 的堆叠图的前视图？

(A)

(B)

(C)

(D)

(E)

Answer

Correct choice: (B)

正确答案：（B）

Solution

Answer (B): The front view shows the larger of the numbers of cubes in the front or back stack in each column. Therefore the desired front view will have, from left to right, 2, 3, and 4 cubes. This is choice B.

答案（B）：正视图显示每一列中前面或后面堆叠的立方体数量取较大值。因此所需的正视图从左到右分别有 2、3、4 个立方体。这是选项 B。

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