A music class consists of 10 girls and 5 boys. In how many ways can 4 girls and 4 boys be chosen?

4 students can be selected out of 15 (10 girls and 5 boys) in (15,4)=1365
C
(
15
,
4
)
=
1365
ways. Again, 2 boys and 2 girls can be selected out of 5 boys and 10 girls in (5,2)∗(10,2)=10∗45=450
C
(
5
,
2
)
∗
C
(
10
,
2
)
=
10
∗
45
=
450
ways.Hence, the required probability is 4501365=3091
450
1365
=
30
91