Answer:
50
Step-by-step explanation:
30% * n = 15
Change to decimal form
.30 *n = 15
Divide each side by .30
.30n/.30 = 15/.30
n =50
The number is 50
 
        
             
        
        
        
Answer:
P(O and O) =0.1296 
P=0.3778 
Step-by-step explanation:
Given that
 blood phenotypes in a particular population
A=0.48
B=0.13
AB=0.03
O=0.36
As we know that when A and B both are independent that 
P(A and B)= P(A) X P(B)
The probability that both phenotypes O are in independent:
P(O and O)= P(O) X P(O)
P(O and O)= 0.36 X 0.36 =0.1296 
P(O and O) =0.1296 
The probability that the phenotypes of two randomly selected individuals match:
Here  four case are possible
So 
P=P(A and A)+P(B and B)+P(AB and AB)+P(O and O)
P=0.48 x 0.48 + 0.13 x 0.13 + 0.03 x 0.03 + 0.36 x 0.36
P=0.3778