1.

How many words can be formed from the letters of the word “DAUGHTER” so that the vowels always come together? (a) 2880 (b) 4320 (c) 3600 (d) 3200

Answer»

(b) 4320

There are eight letters in the word “DAUGHTER” including three vowels (A, U, E) and 5 consonants (D, G, H, T, R) If the vowels are to be together, we consider them as one letter, so the 6 letters now (5 consonants and 1 vowels entity) can be arranged in 6P6 = 6 ! ways. Also corresponding to each of these arrangements, the 3 vowels can be arranged amongst themselves in 3 ! ways. 

∴ Required number of words = 6 ! × 3 ! 

= 6 × 5 × 4 × 3 × 2 × 1 × 3 × 2 = 4320.



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