UPSC NDA Math Model Paper 9

The possible cases can be:
1. 4 boys and 4 girls
2. 3 boys and 3 girls
3. 2 boys and 2 girls
Ways of selecting of 4 boys out of 4=‌4C4=1
Ways of selecting of 3 boys out of 4=‌4C3=4
Ways of selecting of 2 boys out of 4=‌4C2=6
Ways of selecting of 4 girls out of 6=‌6C4=15
Ways of selecting of 3 girls out of 6=‌6C3=20
Ways of selecting of 2 girls out of 6=‌6C2=15
∴ Total possible ways N=(1×15)+(4×20)+(6×15)
N=15+80+90=185