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Ultimate math trick question?

Red Baron Farms

Philosopher
Joined
Apr 30, 2013
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Location
Oklahoma
Was surfing and came across this problem:

When I was 4 years old, my sister was half my age. Now my sister is 12 years old. How old am I?


Then I got to noticing that there was a huge thread of wrong and/or incomplete answers! 1,755 answers and not a single one as far as I could find got it 100% right. Only a very few even got close. So I thought that those of you here who like math puzzles might want to try your hand at it.:D

Will award the complementary 3 thumbs up :thumbsup::thumbsup::thumbsup: to the party getting it completely right, 2 thumbs :thumbsup::thumbsup: for mostly right close but no cigar, 1 :thumbsup: for correct but not complete and :p for using black holes and/or speed of light cheats etc et al.;)
 
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Well in typical communication we say we are "4 years old" for 364 days. For high precision we would need to know the birthdays of both people. I think.
 
Well in typical communication we say we are "4 years old" for 364 days. For high precision we would need to know the birthdays of both people. I think.

And if anybody has a leap year birthday. Damn leap years.
 
An ambiguity I can see arises from a literal reading of

When I was 4 years old, my sister was half my age.

This is (or was) only partly true, unless you and your sister have the same birthday.

A more "normal", that is, non-tricky reading of the phrase is that for most of period that you were 4, your sister was 2, but there was a period at one end or the other when she was either 1 or 3.

If she is now 12, you could be either 13, 14 or 15, depending on birth dates and current date.
 
An ambiguity I can see arises from a literal reading of

When I was 4 years old, my sister was half my age.

This is (or was) only partly true, unless you and your sister have the same birthday.

A more "normal", that is, non-tricky reading of the phrase is that for most of period that you were 4, your sister was 2, but there was a period at one end or the other when she was either 1 or 3.

If she is now 12, you could be either 13, 14 or 15, depending on birth dates and current date.
:thumbsup::thumbsup: Getting closer.
 
I presume this depends on relative birthdays. If I turned four on December 31, and my sister turned three on January 1, then for one day a year, I'd be four and she'd be two. But for the rest of the year she'd only be a year younger.
 
I hope that when the full explanation (the punchline) comes it's cool and educational. Please don't let it be a turd.
 
My boys were born 18 months apart, so for half a year, age wise, they are two years apart, for the other half they are only one year apart.
I suspect someplace therein lies the answer to this mathematical conundrum.
 
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It took all of a handful of posts to layout what should be the big payoff.

"Ultimate" my ass. :rolleyes:
Well several posts from VERY VERY smart people trying to solve a trick question math puzzle and although quite a few are dancing around the answer, still no one got it completely correct yet........including you.

So if you actually want to scoff with disdain, why not answer it correctly first?:D
 
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Well several posts from VERY VERY smart people trying to solve a trick question math puzzle and although quite a few are dancing around the answer, still no one got it completely correct yet........including you.

So if you actually want to scoff with disdain, why not answer it correctly first?:D


I had in mind in three seconds both the normal intended answer and the more detailed "gotcha" explained in later posts. It's not a new puzzler.

But I don't think many have bothered to give the problem a great deal more skull sweat than that. If you've got some deeper angle on the question (please don't go metaphysical)... will we be blessed with the reveal anytime soon?
 
This thread is now twice as boring as it was at the beginning. How old was this thread when it was posted?
 

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