asked 135k views
3 votes
Prove if the sum of the digits of a 3 digit number n is divisible by 9, then n is divisible by 9.

asked
User HotFrost
by
8.0k points

1 Answer

4 votes


n=100x+10y+z\\x+y+z=9k,k\in\mathbb{Z}\\\\n=99x+9y+x+y+z\\n=99x+9y+9k\\n=9(11x+y+k)

answered
User MaxYarmolinsky
by
8.4k points

No related questions found

Welcome to Qamnty — a place to ask, share, and grow together. Join our community and get real answers from real people.