Musings of a Dinosaur

A Family Doctor in solo private practice; I may be going the way of the dinosaur, but I'm not dead yet.

Friday, July 10, 2009

I Figured This One Out

Thanks to Professor B who sent me this internet puzzle: It's one of your basic "think of a number" games where the computer appears to read your mind.

The original email was titled, "Tell me how this works," so I did. Took me about 5 minutes. Non-mathematical hint available.

(NinjaBaker: consider the gauntlet thrown.)


At Fri Jul 10, 01:31:00 PM, Blogger Lazlo said...

Well, mathematical answer here. Don't read further if you want to figure it out yourself. Any number XY is 10*X + Y. If you take (10*X + Y) - X - Y, the Y's sum to zero, so you're left with 10X - X, or 9X. So your answer will necessarily be an even multiple of 9. If you look through the grid, all of the even multiples of 9 (9, 18, 27, 36, etc...) are the same thing which, coincidentally, is the answer they give. Magic! Math! Woot! :)

At Sat Jul 11, 10:12:00 PM, Anonymous Anonymous said...

How funny! I tried it three times and was amazed. Then after reading Lazlo's comment, I realized I only looked at the square with my number. Isn't psychology just fascinating!


At Mon Jul 13, 12:33:00 AM, Anonymous Anonymous said...

The trick is that the right answer (9x)changes each time you play the game.
-whitecap nurse


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