A committee of 3 is to be formed from a group of 2 boys and 2 girls. Here are two boys B1 and B2 and two girls G1 and G2. Sample space =S={B1B2G1,B1B2G2,G1G2B1,G1G2B2} ⇒n(S)=4 A: The event that the committee consists of 2 boys and 1 girl A={B1B2G1,B1B2G2} ⇒n(A)=2 probability that the committee consists of 2 boys and 1 girl =P(A)=
n(A)
n(S)
=
2
4
Hence, A committee of 3 is to be formed from a group of 2 boys and 2 girls, the probability that the committee consists of 2 boys and 1 girl