Question

The probability that a person in the United States has type B​+ blood is 88​%. ThreeThree unrelated people in the United States are selected at random. Complete parts​ (a) through​ (d). ​(a) Find the probability that all threethree have type B​+ blood.

Answer 1

Let , p be the probability that a person in the United States has type B​+ blood.

Since , p=0.88

Therefore , q=1-p=0.12

Now , there are randomly select the three persons.

Therefore , n=3

Let , X be the number of person having blood is B+.

Here ,

Therefore , the pmf of X is ,

; x=0,1,2,.........,n

=0 ; otherwise

Now , we want to find the probability that all three have type B​+ blood.

Therefore ,