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This question already has an answer here:

(It's an old soviet math problem, no tricks or anything here)


Jimmy is 21 years younger than his mother.

Six years from now, Jimmy's mother will be five times as old as Jimmy.

Where is Jimmy's father?

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marked as duplicate by DEEM, JMP, Glorfindel, ABcDexter, Alconja Nov 4 '18 at 22:52

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • $\begingroup$ You should word it as "five times as old" to remove ambiguity. $\endgroup$ – Acccumulation Nov 2 '18 at 19:42
  • $\begingroup$ @ Thomas Blue This question was asked as " Where is Jenifer's Husband" on this site a few years ago. So it is a duplicate. Please check $\endgroup$ – DEEM Nov 4 '18 at 16:27
  • $\begingroup$ @ DEEM That is true. In russian it was called "Where is the father" so my searches for duplicate proved worthless $\endgroup$ – Thomas Blue Nov 5 '18 at 11:19
  • $\begingroup$ No issue. Happens all the time. Funny puzzle though $\endgroup$ – DEEM Nov 5 '18 at 12:47
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Well, first I have to solve the math problem, I guess.

Let $x$ equal Jimmy's age.

This means $x+21$ is the mother's starting age. In 6 years, Jimmy will be $x+6$ and his mother will be $x+27$.

So, $(x+6)*5 = x+27$

$5x+30 = x+27$

$5x + 3 = x$

$4x = -3$

$x = -3/4$

Yeah, I see where this is going. Jimmy is exactly -9 months old, which means his father is right where his mother is, most likely.

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  • 2
    $\begingroup$ Nice! You get the tick! $\endgroup$ – Thomas Blue Nov 2 '18 at 17:02
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Easy math:

Let $x$ represent Jimmy's age.
Let $y$ represent Jimmy's mother's age.

We can convert this into two equations:
$x+21=y$
$5*(x+6) = y+6$

Substituting the first equation into the second equation via isolated y:
$5x+30=x+21+6$

Subtract x and 30 from both sides of the equation:
$4x = -3$

Jimmy is -3/4 years old. This is the length of a pregnancy (9 months).
Jimmy's father is currently sleeping with his mother as he is being conceived.

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  • $\begingroup$ Looks like someone else beat me by a matter of seconds... so close $\endgroup$ – kanoo Nov 2 '18 at 15:05
  • $\begingroup$ Still nice! You get the sympathy and an upvote! $\endgroup$ – Thomas Blue Nov 2 '18 at 17:02
  • $\begingroup$ 1 min 29 sec to be exact... @kanoo Nice job tho, +1! $\endgroup$ – Omega Krypton Feb 9 at 11:22

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