Answer:
22.05
Step-by-step explanation:
21/2 has 5 halves
10.5 divided by 5= 2.1
2.1= 1/2 2.1 x 10 = 21
2.1 / 2 = 1.05
21 + 1.05= 22.05
7/8 is the answer hope this helps
The answer is -8
I found my answer by using desmos. It is the best app for graphing. I wrote the equation and then I looked for the point 18 on the y axis and then I looked where it was on the x axis
that is how I found my answer.
You only need to consider the situations where 10 or 11 of the babies are girls, then subtract those probabilities from 1. This will give probability that any other number up to 9 of the babies are girls.
Use binomial theorem.

n = 11
k = 10,11
p = 1/2