Answer:
Given p = 0.07 as the probability that someone is a universal donor
In case of Geometric Distribution, Probability of getting the first success on nth trial is given by
[tex]P (X=n) = p (1-p) ^ {n-1}[/tex]
where p is the probability of success on any one trial and (1-p) shows the probability of failure.
So the probability of the first subject to be a universal blood donor will be the seventh person is
[tex]P (X=7) = 0.07 (1-0.07) ^ {7-1} = 0.07 (0.93) ^ 6 = 0.07*0.647 = 0.0453[/tex]
So the final probability is 0.0453
