Suppose that |a - b| + |b - c| + |c - d| + .... + |m-n| + |n-o| + ... + |x - y| + |y - z| + |z - a| = 20. What is the maximum possible value of |a-n|?
Since |a-n|= |a - b| + |b - c| + |c - d| + .... + |m-n| and |n-a|=|m-n| + |n-o| + ... + |x - y| + |y - z| + |z - a|, and |a-n|=|n-a|, The maximum value of |a-n| is 10
