• # question_answer Eight different letters of an alphabet are given Words of four letters from these are formed The number of such words with at least one letter repeated is A) $\left( _{4}^{8} \right)-{{\,}^{8}}{{P}_{4}}$     B)         ${{8}^{4}}+\left( _{4}^{8} \right)$   C)         ${{8}^{4}}-{{\,}^{8}}{{P}_{4}}$          D)         ${{8}^{4}}-\left( _{4}^{8} \right)$

Total number of words formed by 4 letters given from eight different letters with repetition $={{8}^{4}}$ and number of words with/no repetition $={{\,}^{8}}P{{ & }_{4}}$ $\therefore$Required number of words $={{8}^{4}}-{{\,}^{8}}{{P}_{4}}$