Not 100% sure this is correct but this seems correct.
Answer:
Step-by-step explanation:
If each day equal chance then p = Prob that a person is borne on a particular day = 1/365
Each person is independent of the other and there are two outcomes either borne in July or not
p = prob for one person not borne in July = (365-31)/365 = 334/365
a)Hence prob that no one from n people borne in July = 
b) p = prob of any one borne in July or Aug =
=0.1698
X- no of people borne in July or Aug
n =15
P(X>=2) =
=0.7505
Simply multiply 4 for the terms in the parenthesis
4x-4
.725 , .572 , .275, .2
You look at the first decimal place to see which is the greatest. 7 is greater than 5 and 2 so it's first. Then 5 is greater than 2 so it is next. For the last two numbers since 2 is the same value you look at the next decimal place. Since 7 is greater than 0 it comes next!
Combine like terms to get 2x + 6x which is 8x and 3y + 9y which is 12y so the simplified answer is 8x + 12y