I’m stumped by this one:
Holmes once had a visit from an old acquaintance whom I had never met before. I found them chatting freely in a way he seldom did with me as I came in to offer them some tea.
“And how are your children?” Holmes was asking. “You have three, if I remember rightly, although I must admit I don’t quite recall their ages.”
“You always enjoyed deduction, didn’t you, old chap?” his acquaintance replied. “What if I told you that the product of their ages was 40?”
“That’s not quite enough information for me to deduce their ages,” said Holmes.
“Alright, well I shall add that the sum of their ages is the number of years we’ve known each other.”
Holmes considered this. “I’ll still need a tad more.”
“Finally, the youngest was our first summer baby, born in July.”
“Ah, I see.”
Holmes suddenly turned to me. “Why don’t you tell this gentleman the ages of his children, then, Watson?”
I balked. “But I don’t know how long you’ve known each other!”
“That doesn’t matter, Watson! You now have enough information to deduce it.”
And indeed I did. How old are the three children?