Number of boys = 5
Number of boys to be selected = 3
Number of combinations (selections) = ...(i)
Number of girls = 4
Number of girls to be selected = 3
Number of selections = ...(ii)
∴ From (i) and (ii), by fundamental principle of counting, the number of selections
= 10 x 4 = 40
Hence, the number of ways in which 3 boys and 3 girls out of 5 boys and 4 girls can be selected = 40
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?