## When Geeks Dine Out

Posted September 30th, 2004 @ 09:51pm by Erik J. Barzeski

To three decimal places, geeks tipping:

$33.33 (repeating) + $6.66 (repeating) is a pair of twenties. Or, well, $40 on your credit card.

### 7 Responses to "When Geeks Dine Out"

Posted 30 Sep 2004 at 10:47pm #I've always wondered...

If you take 1/3 and divide it all the way out to infinity, you have .33333...etc. If you add each digit of that together 3 times, all the way out, you get .99999....etc, all the way out to infinity, which doesn't add up to 1, obviously.

None of my math teachers have been able to answer it.

Posted 30 Sep 2004 at 10:51pm #Mathematicians generally agree that .9999 repeating to infinity is 1. I had an argument with my roommate about it once because it's a difficult concept to grasp (and even harder to explain). I found this link off of google that I used to help explain it: http://mathforum.org/library/drmath/view/53339.html

Posted 01 Oct 2004 at 10:47am #True, but in the real world, you've just confused the piss out of the restauranteur, who's looking at the receipt going, "What the #^%*?! This doesn't add up."

$33.33 + $6.66 = $39.99

It doesn't round up, nor does it appear to equal $40.

I don't know what funky math class you took back in elementary school, but I'd go back and ask for my milk money back.

Posted 01 Oct 2004 at 11:25am #OK, let's say x = .999… (repeating), so we can easily say 10x = 9.999… , savvy?

OK, here's the fun part. We can easily say:

10x - x = ? (9x)

So long as we perform the operation on both sides, we can also say:

10x - x = 9.999… - .999…

Lo, and behold:

9x = 9, x = 1!

Posted 01 Oct 2004 at 2:00pm #drew == damn sexy

Posted 03 Oct 2004 at 10:51am #When Geeks Dine OutWhen Geeks Dine Out

Posted 30 Sep 2005 at 7:58pm #10x-x = 9.99~ - .99~

x(10-1) = .99~ (10-1)

x = .99~

............................

10x-x = 9.99~ - .99~

9x = 9

x = 1

............................

x = 1

x = .99~

.99~ = 1

I hope explaining this way makes it clearer. There are two ways to solve the problem, both giving you "different" answers. You can substitute either into the equation and get the same answer so they must be equal. It is really interesting and confusing.