John wants to visit his friend Mary, but he doesn't know where she lives. Fortunately, he has a map and some information:约翰想去拜访他的朋友玛丽，但他不知道她住在哪里。幸运的是，他有一张地图和一些信息：
- The Island People think of themselves as neighbors if they can visit each other by crossing only one wooden walkway.岛上的居民认为，如果彼此之间只需穿过一条木板路就能互相拜访，那他们就算是邻居了。
- Mary, Zac, and Pan have four neighbors.玛丽、扎克和潘有四个邻居。
- Zac and Pan are neighbors with Niki.扎克和潘是尼基的邻居。
- Niki has no other neighbors.妮基没有其他邻居。
Question:问题:
Where is Mary's house? 玛丽的房子在哪里？
Explanation 解释
Answer: 答案:
House 4 shown below. 如下所示的 4 号房屋。
Explanation: 解释:
To solve the problem, it is necessary to focus on the paths, that go from each house. We first need to identify the houses with four paths. There are three such houses: 4, 5 and 7.
要解决这个问题，有必要关注从每栋房屋出发的道路。首先，我们需要找出有四条道路的房屋。这样的房屋有三栋：4 号、5 号和 7 号。
So Mary, Zac and Pan live in one of these three houses, but we need to find out where exactly Mary lives.所以玛丽、扎克和潘住在这三栋房子中的一栋，但我们得弄清楚玛丽到底住在哪一栋。
The other two pieces of information describe Niki's house. We can deduce that there are only two paths from it. So Niki lives in one of the houses with numbers 1, 2 or 6.另外两条信息描述了妮基的房子。我们可以推断出那里只有从那里有两条路。所以妮基住在 1 号、2 号或 6 号房子中的一所。
As Niki is neighbour with Pan and Zac, we can further deduce that:由于妮基与潘和扎克是邻居，我们还可以进一步推断出：
• Niki lives in house number 6尼基住在 6 号房子。
• Zac and Pan live at numbers 5 and 7 (or the other way around) 扎克和潘分别住在 5 号和 7 号（或者反过来）。Thus, there is only one house with four paths that can be Mary's house. It is the one with the number 4! 因此，只有一座房子有四条路可以通往那里，那座房子可能是玛丽的家。它就是那座有数字4！
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