Question

there are cats got together to decide killing the mice of 999919 each cat kills equal no. of mice and each cat kills more no.of mice than cats there were.then what are the number of cats?

Answer 1

999919 = 1000000 - 81 = 1000^2 - 9^2 = (1000+9)(1000-9) = 1009*991.
Since there were more mice than there were cats, 991 cats killed 1009 mice each.