A number of 50 digits has all its digits equal to 1 except the 26th digit. If the number is divisible by 13, then find the digit in the 26th place.
(In reply to
a little more straightforward by Eric)
If you take out the first and last 24 1s, you'd be left with 1? with 24 zeros afterwards. I suppose that means 10^24 is divisible by 13. Yes, it is...

Posted by Tristan
on 20031116 20:52:59 