AMC 8 2007 Problem 9
AMC8 2007 年第 9 题
逻辑推理（跨域）★★☆☆☆
To complete the grid below, each of the digits 1 through 4 must occur once in each row and once in each column. What number will occupy the lower right-hand square?
为完成下面的表格，要求数字 1 到 4 中的每个数字在表格的每一行和每一列都必须出现 1 次。
则表格的右下角方格里的数字是多少？
- A.1
- B.2
- C.3
- D.4
- E.cannot be determined / 无法确定
正确答案 · Correct Answer
B
解析 · Solution
Solution 1
The number in the last column of the second row must be 1 1 because there are already a 2 2 and a 3 3 in the second row and a 4 4 in the last column. By similar reasoning, the number above the 1 1 must be 3 3. So the number in the lower right-hand square must be 2 2. This is not the only way to find the solution. 1 2 3 2 3 1 4 2 1 2 3 2 3 1 4 2 The completed square is 1 4 2 3 2 3 4 1 3 2 1 4 4 1 3 2 1 2 3 4 4 3 2 1 2 4 1 3 3 1 4 2 Answer: 𝐵 B .
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