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

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

So the final probability is 0.0453
The second and the third one because first is the same as 3 4/7 and 81=3^4
Answer:
Option B.
Step-by-step explanation:
The given quadratic equation is

We need to find the solution of given quadratic equation.
Divide both sides by 9.


Taking square root on both sides.


The solution of given equation are
and
.
Therefore, the correct option is B.
10.99x = 3.99x + 280
7x = 280
x = 40
They must sell 40 T-shirts to break even