A person writes letters to six friends and addresses the corresponding envelopes
MATHEMATICS · Single correct · CBSE · Mathematics · Permutations and Combinations · Permutations and Combinations
Problem
A person writes letters to six friends and addresses the corresponding envelopes. Let x be the number of ways such that at least two letters are in wrong envelopes, and y be the number of ways such that all letters are in wrong envelopes. Then x−y is equal to
(1) 719
(2) 265
(3) 454
(4) None of these