Asked by Hannah

There are 9 girls and 11 boys on maths team 2 members get chosen for represent the school what is the probability that the 2 will be of the same sex please show me the working out too thank you
Answered by scott
there are 20C2 ways to pick two members

there are 9C2 ways to pick two girls , and there are 11C2 ways to pick two boys

the probability of same sex is ...(9C2 + 11C2) / 20C2