Two men meet on a street in moscow. They know each other vaguely, and they stop to chat about their families. When the topic of children comes up, the first man says to the second man "Ah, I remember your three sons. How old are they now?"
The second man replies "I will not tell you their ages, but I will give you a clue. The product of their ages is 36".
The first man then says "that is not enough information. I need another hint"
The second man says "Ok, the sum of their ages is equal to the number of windows on the building across the street."
The first man counts the windows on the building and thinks. He then says "ok, I almost have it, I just need one more clue"
The second man says "My oldest son has red hair!"
The first man exclaims "Ok! I know their ages!"
The second man replies "I will not tell you their ages, but I will give you a clue. The product of their ages is 36".
The first man then says "that is not enough information. I need another hint"
The second man says "Ok, the sum of their ages is equal to the number of windows on the building across the street."
The first man counts the windows on the building and thinks. He then says "ok, I almost have it, I just need one more clue"
The second man says "My oldest son has red hair!"
The first man exclaims "Ok! I know their ages!"