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Problem

生育政策与男女比例 (Fertility Policy)

Problem

Question

If a family stops having children after giving birth to a boy, and continues to have children after giving birth to a girl until a boy is born, the question is: What will the gender ratio be in this place?

如果一个家庭生下男孩就不再生孩子，如果是女孩子就继续生，直到生出男孩为止，问：这个地方的男女比例会是多少？

The Sock Drawer

Problem

Question

A drawer contains red socks and black socks. When two socks are drawn at random, the probability that both are red is \(\frac{1}{2}\)

(a) How small can the number of socks in the drawer be?

(b) How small if the number of black socks is even?

一个抽屉里装有红袜子和黑袜子。 当随机抽取两只袜子时，两只袜子都是红色的概率为\(\frac{1}{2}\)

(a) 抽屉里的袜子数量最少可以是多少？

(b) 如果黑袜子的数量是偶数，最少可以是多少？