Brain Teasers
What is the 10 Digit Number?
There's a certain 10-digit number where that the first digit is equal to the number of zeros in the entire number, the second number is the number of 1's in the entire number, the third number is the number of 2's in the entire number, and so on, to where the 10th digit is the number of 9's in the entire number.
What is the number?
What is the number?
Answer
6210001000There are 6 zeros, 2 ones, 1 two, 0 threes, 0 fours, 0 fives, 1 six, 0 sevens, 0 eights, and 0 nines.
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Comments
the answer could also be 9000000000
Elaine, it can't be 9000000000, as the last digit would have to be a 1 (there is one 9), and then the second digit can't be 0, and so on.
Jun 02, 2003
You're both wrong the answer is 6210001000
Jun 10, 2003
can't it also be 6122000000?
It can't be 6122000000. The number you have written has six "0's" and one "1" and two "2's" but it doesn't have two "3's"
i'm no good at logic teasers. good1 though!
Nice one for sure! Has anyone got a proof to demonstrate that there is no other possible answer. I got to this answer by starting at 9 000 000 000- but could there be any other.
I'm pretty sure I got another right answer. I got 8000000010
I'm afraid not, Heather. As your number, 8000000010, has one 1 in it and the 2nd digit (to represent the number of 1's) is zero. I'm not sure if the answer is unique, I'll need to give it some serious thought...
i am only a logical thinker in real situations...not in brain teasers lol
Jun 30, 2003
This was the wrong day to get a number logic teaser... I already have a headache and that just made it worse..lol.. but it was definitly a great teaser... i wanna know how u made that one up.. did u try all the other possible combo's???
THE NUMBER CAN BE 8100000000
The number can't be 8100000000 because in the spot where the number gives the number of "eights" you have a zero when you really have one-"eight" showing.
Obviously,6210001000.
It is a number abcdefghij with a 0's,b 1's,...,and j 9's.
It is a number abcdefghij with a 0's,b 1's,...,and j 9's.
to cavtfree - he/she made it up by going on to www.flooble.com/perplexus and copying it straight from there. If you don't believe go to that website and search for the puzzle "self descriptor".
it took me 10 seconds to figure this one out, but it was fun
One thing to note is that the sum of the ten digits must be 10. This would indicate that most of the digits in the number would have to be small, eliminating a lot of possibilities. From there, it is a little trial and error with some common sense.
Lovely problem!
If people are interested in a proof, this seems to be a pretty good website. I'm not affiliated.
http://begghilos2.ath.cx/~jyseto/Academia/Math-Problem-1.php
If people are interested in a proof, this seems to be a pretty good website. I'm not affiliated.
http://begghilos2.ath.cx/~jyseto/Academia/Math-Problem-1.php
I'm impressed. I've only done up to seven digits.
I'm impressed. I've only done up to seven digits.
Absolutely loved this one! It as great except if you copied it, if not good job!
good one! i'm usually good at these, but i was confuzzled at this one!
very interesting but i would have needed alot of time to fiqure that out.
too hard, and too confusing. sorry. good, though, i guess!
Mar 20, 2008
it can be 8100000000
Mar 20, 2008
never mind, maybe i should have read the other comments first... lol
It is Impossible because the last digit would have to be 1 therfore the first digit would have to be 9 however the number 1000000009 doesn't work. It is impossible, unless the first digit is the one to the far left (which technically is the last).
Nevermind
Fantastic puzzle! Great!
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