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?
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?