I think you mean circumference...Area is
. We have the area so we need to use it to solve for the radius which we will then use in the circumference formula.
. Divide both sides by pi to get
. Of course the simplification of the left side gives us
and r = 4. Now fill that in to the circumference formula, which is
, to get C
which is a circumference of
Subtract 250-50 which equals 200 and then multiply it by 3 which is 600
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
Are you trying to figure out the value of n?