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.

For a given number to be divisible by 13, the sum of all the digits of the given number must be divisible by 13.
So when we add the 50 digits we get
(49+26th digit) which has to be divisible by 13.So the smallest value should be 3 which satisfies the given condition.
So the 26th digit has to be 3.

Posted by Purna on 2004-01-24 06:17:38