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Jennifer is 21 years older than her son Douglas. 6 years from now, Jennifer will be 5 times as old as Douglas.

Question: Where is Jennifer's husband most likely to be right now?

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    $\begingroup$ This really is more of a joke than a puzzle. $\endgroup$ – xnor Mar 18 '15 at 21:04
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    $\begingroup$ @xnor Well, it does have a clear solution as to the ages of Jennifer and Douglas. And in the original version, there was a "where is he most likely to be?" disclaimer, which cuts out a lot of the nitpicks from the two joke answers below. $\endgroup$ – Rand al'Thor Mar 19 '15 at 0:37
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    $\begingroup$ Jennifer's husband is fishing in Canada. (with apologies to Raymond Smullyan) $\endgroup$ – David Mar 19 '15 at 2:14
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    $\begingroup$ Perhaps the puzzle could be improved by changing the final question to "Where is Douglas's father?" $\endgroup$ – R.. Mar 19 '15 at 5:47
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    $\begingroup$ The original question was not phrased well. I had edited it to resolve that, not realizing the importance of the "most likely" part. I've edited again, restoring that key aspect of the question. :) $\endgroup$ – JakeRobb Mar 19 '15 at 14:18
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Let's define $J$=Jennifer and $D$=Douglas.
The problem can be rewritten as:

$J=D+21$
$J+6=5(D+6)$

According to my math, Douglas is $D=(-\frac{3}{4})$ years old, which means $-9$ months. Pregnancy lasts for nine months, so Jennifer's husband is in the bed with her right now.

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    $\begingroup$ That's actually the milk man.. $\endgroup$ – blakeoft Mar 18 '15 at 18:18
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    $\begingroup$ Actually, you can't know yet whether Douglas is a male or a female... $\endgroup$ – leoll2 Mar 18 '15 at 18:21
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    $\begingroup$ actually they may not be in bed. But he's most probably inside her $\endgroup$ – Novarg Mar 18 '15 at 19:05
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    $\begingroup$ @leoll2 - "Actually, you can't know yet whether Douglas is a male or a female". Yes, and I can imagine some feminist visiting this post and calling all of us "male chauvinist pigs". :P $\endgroup$ – User Anonymous Mar 19 '15 at 5:06
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    $\begingroup$ To be nitpicky, human gestation averages 280 days. The number of days in 9 months is between 273 and 276, depending on which month you start counting from, so we can really only say Jennifer's husband will be in bed with her - on average - within the next 7 days. And even if you massaged the numbers to pinpoint the day, you can't be sure they are in bed right now, you could be a few hours off due to rounding errors. $\endgroup$ – Michael Mar 19 '15 at 16:36
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Jennifer's husband is busy in business meetings, while Douglas's dad is with Jennifer.

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    $\begingroup$ I was wondering when someone was going to give this kind of amswer, ahahah $\endgroup$ – Marco Bonelli Mar 19 '15 at 13:04
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As mentioned in leoll2's answer above, the Maths part of the question is the simultaneous solution of the two equations which relate the respective ages of Jennifer and Douglas:

$$J=D+21$$ $$J+6=5(D+6)$$

These provide the answer $D = -3/4$ years, or roughly $-9$ months, which could lead one to conclude what leoll2 concluded.

However,

1) It is not necessary that Jennifer's husband must have necessarily fathered Douglas. (No offence meant, I only mean it is not specified in the puzzle.)

2) Biologically, pregnancy doesn't always have to last 9 months. So, one can not deny the possibility of Douglas being born after 8 and a half months instead of nine.

So, Jennifer's husband could be anywhere in this world, or could even be dead. Particularly, if he hasn't fathered Douglas, and pregnancy did last exactly 9 months, then he must not be around at the time of conceiving (stark opposite conclusion from the same data).

This is not a well designed puzzle. Sorry for being a killjoy :(

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    $\begingroup$ well you're no fun $\endgroup$ – basher Mar 18 '15 at 19:44
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    $\begingroup$ @basher - I know, but I think I'm not oversimplifying :) $\endgroup$ – User Anonymous Mar 18 '15 at 19:47
  • $\begingroup$ Plus, the best part of having rep 1 is an immunity to possible down-votes :P $\endgroup$ – User Anonymous Mar 18 '15 at 19:48
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    $\begingroup$ -1 The trick of solving a puzzle is understanding the puzzle, this puzzle clearly required thinking in generalized terms and this answer clearly fails at that. And if you actually feel sorry for being a 'killjoy', there is a simple solution: just don't post answers like this ;-) $\endgroup$ – David Mulder Mar 18 '15 at 23:20
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    $\begingroup$ Yes, and as mentioned in my other comment, human gestation actually averages 280 days, which is up to a week beyond nine months, depending on which months are included. $\endgroup$ – Michael Mar 19 '15 at 16:37

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