Natural Numbers

[Acedeal]

The Natural Numbers are written successively as shown below:
12345678910111213141516..........., such that the 4th digit is '4' the 9th digit is '9' but the 11th digit is '0', the 15th digit '2', the 17th '3', and so on.
What is the 40,000th digit that appears in this list ?

[[FS]WhiteTiger2225]

i think it would be 0

[Acedeal]

Nope,
you also have to post how you came up with the answer.

[Panda]

The Answer is 1...

Pretty much I approached this by looking at how many digits come from single digit numbers (where you get digits 1-9), double digit numbers (where you get digits 10-189), triple digit numbers (where you get digits 190-2889), and did so until I reached at total of 40,000 or above (that occured on the 5 digit numbers).

Here's an example of how to get these ranges....
For two digit numbers you get the final range digit by 2*90+9=189. You add the 9 because you've already moved up 9 digits and we know that there are 90 2 digit numbers. You can follow this pattern to get all of the digit ranges for 3, 4, and 5 digit numbers.

Thus it's the 5 digit numbers that are crucial. The digits 38890-488889 are from these.

We now know that we are looking at the 1111 digit from the 5 digit numbers because that's the 40,000th digit.

A slight adaptation from the pattern I just gave you tells us that 1111=222*5+1. From that we can conclude that we want the first digit of the 223 5 digit number. That's not too hard to find....10222 would be that number. The first digit of that number is the 40,000th digit. So the answer is 1.

I hope that all made sense. This was a similar problem to a "just for fun" problem in one of my math classes from last year.

[Tatmtt2120]

NERD ALERT, NERD ALERT, NERD ALERT, NERD ALERT, NERD ALERT, NERD ALERT, NERD ALERT, NERD ALERT, NERD ALERT :D

[Panda]

Ouch! That hurts... :(

[-=DoW=- Deze]

"just for fun"

One question!? :shock: ......... Where is the fun?? :? If this was a "just for fun" problem for you, please change your name to:
<center>-=DoW=- DropDeadEinstein :D :banger: </center>

I would NOT even try to solve one of the "real" problems you get in your math classes :lol:
Have you ever taken a IQ test??

[-=DoW=- po632003]

DOH!!!!! :shock:

[Panda]

I think the second half of the explanation you gave Ace is what I did. Sweet! I was right! Hehe. :P

Deze, the problems we actually did in the class were a bit more difficult, but it's hard to compare. Just because they were different. The "just for fun" problem was more of a brain-teaser. It is in no way a representation of what we did in that class. And yes, I did take an IQ test when I was young, but that score is a bit private.

Math has just always been my thing. It makes sense to me. :mrgreen:

[Tatmtt2120]

And yes, I did take an IQ test when I was young, but that score is a bit private.



He must have failed. :lol: :lol: :lol: :lol:

[-=DoW=- Body Piercer]

:lol: :lol: Quit pickin on the kid with the big brain, he'll get a complex. Oh yeah, how come you didn't fire off one of those nerd alert strings at Acedeal for the explaination? :twisted: :twisted:

[5thColumn]

I did an IQ test once but they did not know how to score a negative result.

[Panda]

:lol: :lol: Quit pickin on the kid with the big brain, he'll get a complex.

Yeah, you never know, I might hit you with a calculator. :lol: