# Can you tell me how this works??

Discussion in 'Community' started by MacDawg, Aug 26, 2004.

1. ### MacDawg macrumors P6

Joined:
Mar 20, 2004
Location:
"Between the Hedges"
#1
This was sent to me by my boss... and he wants to know how it works.

http://www.dslextreme.com/users/exstatica/psychic.swf

I could rack up some great points if I could explain it to him, but I don't have a clue. I know that if anyone can tell me, it is you guys here. Can you help?

Joined:
Aug 19, 2004
Location:
Manchester
#2
The limited number of possible answers to the formula are linked to the same symbol. Notice how 9, 18, etc. always share the same symbol? It "knows" which symbol you're going to choose because you have no choice. The trick is that it changes the symbol allocated to that set selection of numbers each time.

I think that explanation makes sense...

3. ### Bruce Lee, PhD macrumors member

Joined:
Jun 10, 2004
#3
here's a hint in two parts:

1. any 2-digit number can be written as 10*a + b, where a and b are integers between 0 and 9.

2. take a close look at the symbols each time a new game starts.

4. ### jsw Moderator emeritus

Joined:
Mar 16, 2004
Location:
Andover, MA
#4
Exactly.

The only possible results are:

9, 18, 27, 36, 45, 54, 63, 72, and 81.

i.e., 9*x, where 1 <= x <= 9

Just confirmed with little Java app (literally did all 90 possible combinations programmatically, kept track of results, printed only numbers which arose - each came up 10 times - although of course this is provable mathematically as well - just too early for me to attempt that!). As noted above, these always have the same symbol as each other, and it changes each time.

Edit: Bruce Lee, PhD is clearly more awake than I am! See above... any number is 10*a + b, therefore all answers are of form:

(10*a + b) - (a + b) = 9*a,

so, because 1<=a<=9, this produces the results above. Coffee would have helped...and, yes, I can program when half asleep, but can't otherwise think clearly.

Joined:
Aug 19, 2004
Location:
Manchester
#5
Uhhh.... fire bad, tree pretty...?
I just stuck some numbers in and noticed that the symbols were always the same. Guess that's why I'm a tech writer and not a programmer.
Isn't it, like, first thing in the morning over there? You guys must have some strong coffee.

6. ### jsw Moderator emeritus

Joined:
Mar 16, 2004
Location:
Andover, MA
#6
Bruce Lee, PhD probably had some. But I just followed his trail of bread crumbs.

7. ### yellow Moderator emeritus

Joined:
Oct 21, 2003
Location:
Portland, OR

Joined:
Aug 19, 2004
Location:
Manchester
#8
Coffee? Or the mind-reading trick.

MacDawg now has a fun trip into an office politics minefield; does he explain it my dumbed-down way, and not look as bright as he could, or does he lay some algebra on his boss and risk making him feel stupid?

9. ### MacDawg thread starter macrumors P6

Joined:
Mar 20, 2004
Location:
"Between the Hedges"
#9
Thanks guys!!
I get it now... but a neat little trick! I had not noticed that the symbols changed with the numbers each time, but it all makes sense now! I guess its like anything else, once you know the trick it doesn't look that difficult anymore!

Thanks again guys! I knew someone would be able to answer it right off!

I'll be a hero with my boss now, thanks to all of you!

Joined:
Jun 10, 2004
11. ### MongoTheGeek macrumors 68040

Joined:
Sep 13, 2003
Location:
Its not so much where you are as when you are.
#11
Actually it only looks like the symbols that go with the relevant numbers change every time.

12. ### sushi Moderator emeritus

Joined:
Jul 19, 2002
Location:
キャンプスワ&#
#12
???

Seems like many change to me.

Pick a number not divisable by 9 and watch it as you refresh. On my screen it is different every time.

Sushi

13. ### goodwill macrumors regular

Joined:
Jan 8, 2004
Location:
London
#13
It has so much to do with the symbols changing each time. Its amazing how the mind and eye slip up and don't notice small details in something like this. I love this kind of thing though. For the longest time, I couldn't figure it out for the life of me.

14. ### themadchemist macrumors 68030

Joined:
Jan 31, 2003
Location:
Chi Town
#14
I remember seeing this about a year ago. My dad freaked out his class with it; then he showed me; and then I made it not so fun or mysterious anymore.