I got an assigment for homework and haven't got a clue about how to solve it, it goes as follows:
"Given a set of 12 integers, demonsrate that the subtraction of 2 integers of said set is divisible by 11"
Any help? Thank you.
What this seems to mean is that in any set of twelve integers, there is at least one pair whose difference is divisible by 11.
Hint: use the pigeonhole principle when looking at the remainders when each of your twelve integers are divided by 11.