What is the smallest integer greater than 0 that can be written entirely with zeros and ones and is evenly divisible by 225?

(In reply to Idea by Gamer)

I agree with the answer 11,111,111,100. As 225 is 9*25, the number of ones has to be 9 (or a multiple of 9, but that would make it bigger), and since 2's and 5's are not permitted in the answer, the number must end in two zeros to be divisible by 25.

Posted by Charlie on 2003-04-08 03:50:39