Question
In how many ways can a team of 3 boys and 3 girls be selected out of 5 boys and 4 girls?
Solution
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
