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

$\begin{array}{1 1}(A)\;350\\(B)\;360\\(C)\;370\\(D)\;380\end{array} $

1 Answer

  • $nP_r=\large\frac{n!}{(n-r)!}$
MONDAY has 6 letters
4 letters are taken at a time
Number of words =$6P_4$
$\Rightarrow \large\frac{6!}{(6-4)!}$
$\Rightarrow \large\frac{6!}{2!}$
$\Rightarrow \large\frac{6\times 5\times 4\times 3\times 2\times 1}{2\times 1}$
$\Rightarrow 360$
Hence (B) is the correct answer.
answered May 13, 2014 by sreemathi.v

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