Please do NOT post your answer, but do say if you think you have solved the puzzle and how long it took. Solution on Monday.

Right now a mother is 21 years older than her child, but in 6 years her child will be 5 times younger than her. Where is the father?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

1. Anonymous says:

Ooh Matron!
2 minutes (to solve the puzzle, that is)

1. Mike Ryan says:

Done.

2. Immediately got it, but I was really put off by the term ‘5 times younger than’. That is a nonsense.

3. Onan, sorry I meant Anon says:

Great to hear that you have “come” up trumps again, your Lordship.
Perhaps you now have time to “spill the beans” regarding your two answers to Richard’s 6/12/13 puzzle?

4. Jugh Janus says:

On top of the mother!

5. Onan, sorry I meant Anon says:

We are all ears.

2. Phil H says:

Hmm, interesting

3. kroketje says:

I have “come” to the right answer in 3 minutes…

1. Roland says:

Are you always so quick? 😉

4. top says:

Hmmmp, interesting!

5. Neil says:

What does 5 times younger mean? If one fifth Mum’s age I have a reasonable answer. If it means the child is 5 times the child’s age younger the answer is not clear.

1. Ed Wilson says:

Agreed – “5 times younger” is not arithmetically clear.

2. Ed Wilson says:

Similarly, is “three times bigger” the same as “four times as big”?

3. Bert says:

I take it to mean that m+6 = 5c, but that makes the kid out to be several years old, which doesn’t seem to agree with what commenters are implying.

4. Kristian says:

@Bert Remember that both of them age.

5. Bert says:

Ah, yes. Silly me.

6. Eddie says:

Is that ‘Where is the father?’ relative to the mother? If so, can’t be ascertained.

7. I demand a DNA test before I incriminate myself!
Happy new year all

8. Anonymous says:

Got it! 5 mins cos I have just woken up….. Saucy!

9. Baker's Dozen says:

Working of course. Unless you’re referring to Broken Britain.

10. Easy: The Daily Mail says he’s on Jeremy Kyle 😉

11. * Blush! *

(2 minutes)

12. Guessed it immediately, but about 2.5 mins to confirm using Hard Sums.

1. Mick says:

Same here.

Oh no.
I guess they didn’t use one.

14. Paul says:

Where is the father? I couldn’t conceive…

15. Alan says:

took a few minutes, but I think I got it

16. Lazy T says:

Well if the mother set off from Leeds at 10 o’clock, on a train heading south at 82 mph, then the father….mmmh

17. I’m embarrassed, and not just for making many errors in the fancy math.

18. sonika says:

don’t determined

19. Mike Torr says:

Oh how I wish the intended answer were true. Unfortunately, it isn’t – because there is a flaw in the thinking 🙂

1. Anders says:

MikeI’m not sure how religious richard is, but to most bible thumpers, their father is always in (as in our father who art inheaven, but perhaps I should focus more on the sane answers

2. Pro-Life says:

20. Timo Pääkkö says:

Think I ve got it,took about an hour…

21. It took me about 5 minutes to work out that “5 times younger than” was probably supposed to mean “a fifth of the ago of”, and then about 20 seconds to work out the answer.

22. Niva says:

Very cute. Can use basic algebra to solve, but if you think about it, there can only be two possible answers with the given info.

23. Anonymous says:

Hahahahah XD loved the puzzle

24. Judi Gait says:

Haha! 2 min.

25. Gene says:

Doh! About 2 minutes to “get” it.

1. Greg says:

Took me a day. Got it thanks to a hint in a comment above.

26. Slange Navarr says:

Seminal puzzle!

Couple of minutes. But I’m not saying to do what.

27. Simon says:

Embarrassingly long for a mathematical physics graduate.
I probably spent too much time studying maths and physics in my youth to make much sense of the answer.

28. Dan Broderick says:

Terrible puzzle, there can be no right answer if you use any reasonable definition of the word child

1. Bert says:

I don’t think you have much grasp on what’s reasonable and what isn’t.

29. This is weird. What in the world does “five times younger” even mean? how can I do a puzzle with undefined terms?

30. Stephen, I got the first letter and every an individual after EXCEPT Margaret Cho’s. Can you remedy that, please?