In how many ways can a student choose a programme of 5 courses if 9 courses are available and 2 specific courses are compulsory for every student?
The word is 'INVOLUTE'
Number of consonants = 4
Number of vowels = 4.
The words formed should contain 3 vowels and 2 consonants.
The problems becomes:
(i) Select 3 vowels out of 4.
Number of selections =
(ii) Select two consonants out of 4.
Number of selections =
(iii) Arrange the five letters (3 vowels + 2 consonants) to form words.
Number of permutations = 5!
(iv) Apply fundamental principle of counting:
Number of words formed =
=
= 4 x 6 x 120 = 2880
Hence, the number of words formed = 2880
A committee of 7 has to be formed from 9 boys and 4 girls. In how many ways can this be done, when the committee consists of :
(i) exactly 3 girls? (ii) at least three girls? (iii) at most 3 girls?