Permutation: n Different Things Taken All at a Time When All Are Not Different.
The letters o...
Question
The letters of word 'postage' are to be arranged in the following manner: (i) Vowels occupy even places. (ii) Consonants are always together.
What will be number of words formed in (i) and (ii)?
Open in App
Solution
Letters 7,V3(a,e,o),C4(p,s,t,g) Total =7! (i) Three even places 2nd,4th and 6th in which 3 vowels can be fixed up in 3! ways and the remaining 4 consonants can be fixed up in 4! ways. Thus the total is 3!.4!=6×24=144. (ii) Consonants together. Follow sting method. Total number =4!.4!=576