In a group of friends, each two people have exactly five common acquaintances. Prove that the number of pairs of friends is divisible by 3.
There are two numbers \(x\) and \(y\) being added together. The number \(x\) is less than the sum \(x+y\) by 2000. The sum \(x+y\) is bigger than \(y\) by 6. What are the values of \(x\) and \(y\)?