The number of words, with or without meaning, that can be formed by taking 4 letters at a time from the…

The number of words, with or without meaning, that can be formed by taking 4 letters at a time from the letters of the word 'SYLLABUS' such that two letters are distinct and two letters are alike, is

Solution

From the given word, S-2,L-2,A,B,Y,U.

Number of alike letter pairs =2

Number of ways to select one pair=C12

Number of distinct letters=5

Number of ways to select two distinct letters=C25

Number of ways to arrange four letters if two are alike=4!2!

Required number of ways =C12C25·4!2!=2·10·242=240

Asked in: JEE Main 2020 (05 Sep Shift 1)

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