AMC 8 1989 Problem 20
AMC8 1989 年第 20 题
立体几何★★★☆☆
The figure may be folded along the lines shown to form a number cube. Three number faces come together at each corner of the cube. What is the largest sum of three numbers whose faces come together at a corner?
此图可以沿所示线条折叠形成一个数字正方体。正方体的每个角上有三个数字面汇聚在一起。汇聚于一个角的三个数字之和最大是多少？
- A.11
- B.12
- C.13
- D.14
- E.15
正确答案 · Correct Answer
D
解析 · Solution
Solution 1
The highest sum of three different numbers on this cube is 4 + 5 + 6 = 15. But 4 and 6 are on opposite faces, so the faces labeled 4, 5, and 6 will not meet at a corner.
The next highest sum of three different numbers on this cube is 3 + 5 + 6 = 14. These faces meet at a corner, so the answer is 14.
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