Combinatorics · Binary words · Prefix free sets · Counting
Words are built from the two letters \(A\) and \(B\) only. Is it possible to form a set of words containing \(3\) words of \(4\) letters, \(10\) words of \(5\) letters, \(30\) words of \(6\) letters and \(5\) words of \(7\) letters, so that no word of the set begins with another word of the set?
Sign in to check answers, open hints, read the full solution, and track your progress. Statements are always free.
Serbian Municipal Competition 2001, high school grade I, category A, problem 5. Organized by the Mathematical Society of Serbia (DMS). Source