题面摘自 Henry E. Dudeney 公版文本；英文为古腾堡原文整理，中文为本站自译，提示、解答骨架和闲谈保留本站原创结构。
Here is a funny little age problem, by the late Sam Loyd, which has been very popular in the United States. Can you unravel the mystery? The combined ages of Mary and Ann are forty-four years, and Mary is twice as old as Ann was when Mary was half as old as Ann will be when Ann is three times as old as Mary was when Mary was three times as old as Ann. How old is Mary? That is all, but can you work it out? If not, ask your friends to help you, and watch the shadow of bewilderment creep over their faces as they attempt to grip the intricacies of the question.
这是已故萨姆·洛伊德提出的一个有趣的小年龄问题，在美国非常受欢迎。你能解开谜团吗？玛丽和安的年龄加起来是四十四岁，当玛丽是安的一半时，玛丽的年龄是安的两倍，当安是玛丽的三倍时，当玛丽是安的三倍时。玛丽几岁了？仅此而已，但是你能解决吗？如果没有，请让你的朋友来帮助你，当他们试图抓住这个问题的复杂性时，观察他们脸上浮现出困惑的阴影。
提示 1
先说出现象：哪些量会变，哪些约束不会变。
提示 2
找守恒量、相似关系、平衡条件或不变量，不急着代公式。
提示 3
把物理图景或谜题结构翻成一个最小方程组，再处理边界情况。
完整解答
解题主线是先把 Dudeney 谜题 21 的条件整理成一个稳定模型，再选择最少的变量。第一步确认约束，第二步写出关键关系，第三步检查特殊情形。这里给的是原创解法骨架；若要核对原始题面，请回到公版来源。
这类题最怕一上来套公式。先把图景或语言条件说清楚，答案通常会少绕很多路。