" Oh well, you win some and lose lots."
Adrian, In this case, you win, win and win again. All three correct answers. I hope this goes some way to alleviate your sense of injustice. I am sure you Brits can bounce back from such an unfair result.
"Try, I am glad you decided to post some more riddles."
Relative, thank you for your kind sentiment. It is somewhat ironic that your post follows that of Adrian who with the comment, "Keep them coming" was responsible for the development of this thread.
Now, for an apology.

I am sorry to say that I have destroyed the notes relating to the ?'Clock' puzzle.
"Two clocks were recently both wound up and set off together at 12 o'clock. They now both show 12.30.
One clock loses ten minutes ever hour and the other gains ten minutes every hour. What is the correct time?"
From memory, it is indeed 36 hours later. One would be 15 minutes fast, the other 15 minutes slow. Should I find the full correct answer, I will of course supply it.
Mathematician & Philosopher Solution
"The product of their ages is 36, and the sum of their ages is the same number as the house where we played chess."
The prime factors of 36 are 2 * 2 * 3 * 3 = 36, so either
(a) the three ages can be got from these four factors - for example,= 4 (=2*2), 3 and 3 is one possibility - or
(b) one of the children is aged 1, and the other two ages can be got from these factors, or
(c) two of the children are aged 1, and the other is aged 36 (unlikely).
This gives the following possibilities.
Product of Ages Sum of Ages
4 * 3 * 3 = 36 4 + 3 + 3 = 10
2 * 6 * 3 = 36 2 + 6 + 3 = 11
2 * 2 * 9 = 36 2 + 2 + 9 = 13
1 * 4 * 9 = 36 1 + 4 + 9 = 14
1 * 6 * 6 = 36 1 + 6 + 6 = 13
1 * 3 * 12 = 36 1 + 3 + 12 = 16
1 * 2 * 18 = 36 1 + 2 + 18 = 21
1 * 1 * 36 = 36 1 + 1 + 36 = 38
There are no other possibilities. Therefore, the house number must be 10, 11, 13, 14, 16, 21 or 38.
We know that this is not enough information for the Mathematician to solve the problem, even though he already knows the house number he is looking for. Therefore he must have found two possible solutions to the problem, and does not know which is correct.
House number 13 is the only one for which there is two solutions (2, 2, 9 and 1, 6, 6), and when the Philosopher refers to his oldest child we know that he cannot have a set of twins followed by a younger child, so the answer must be 2, 2 and 9.
One of the following is a paradox, the other is not.
(A) I always lie
(B) Is "No" the answer to the question?
The answer is B.
If you answer Yes that No is the correct answer then No is really the answer. If you answer No, then you imply that No is not the correct answer and that it should be Yes. This is impossible and the question is a paradox.
In example A, if this statement is true, then the statement is a lie and means that on least one occasion the person has told the truth. If the person is not telling the truth now, this also means he has told the truth on at least one occasion. Hence this statement is simply untrue and not a paradox.
In an effort to raise the standard from plain ?'difficult' to, ?'near impossible' I leave this for your consideration.
If I am spoken of as the first,
My peers are mostly greater than I.
Yet when I'm further down the order,
An excess of me means you could die.
Although I may rise and I may fall,
I have but one more claim to fame:
I am with the merchants all the time.
So I ask you now, what is my name
Two fathers and two sons went fishing. Each caught exactly one fish and yet there were only three fish caught. What is going on
Brown, Jones and Smith are a doctor, a lawyer, and a teacher. The teacher, who is an only child, earns the least money. Smith, who married Brown's sister, earns more than the lawyer. What is each man's job