Answer: 1.4259
Explanation: Square 2 1/2 comes up with 6 1/4 then square root that then multiply by 1/3
1/2 chance of one baby being a boy
1/2*7
7:2 chance
A:4*7=28. so there are 7 multiples upto 30. P(A)=7/30
B:26,27,28,29 i.e. 4 numbers satisfy the 2nd criteria. P(B)=4/30
P(A∩B)=1/30 (since 28 belongs to both A&B)
P(A∪B)= P(A)+P(B)-P(A∩B)= (7+4-1)/30= 1/3