How many words, with or without meaning that can be made from the letters of the word ‘MONDAY’, assuming that no letter is repeated if 4 letters are used at a time.

Explanation

i) Since 4 letters are used.at a time, required number of words `= ^6 P_4`
``
=6 !/(6-4) !=6 !/2 !=6 xx 5 xx 4 xx 3 xx 2 !/.2 !=360
``
ii) Since all letters are used at a time, the required number of words `=6 !=6 xx 5 xx 4 xx 3 xx 2 xx 1=720`
iii) All letters arè used fix `O` at first, then number of words `= ^5 P_4=5 !/1 !=120`
Fix `A` at first, then the number words `= ^5 P_4=5 !=120`. The required number of words `=120+120=240`