Q.

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 ________.


Ans.

(240)

The word SYLLABUS consists of

2S, 2L, 1Y, 1A, 1B, 1U

Required number of ways=C12×C25×4!2!

                                                     =2×10×12=240