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.

(Responding to Ady TZIDON)

That's a nifty approach, but don't we count digits beginning at the decimal? If so, you still might get a variant of your method to work.

Posted by NK on 2004-02-10 18:13:08