A shipment of 20 similar laptop computers to a retail outlet

A shipment of 20 similar laptop computers to a retail outlet
contains 3 that are defective. If a school makes a random purchase of 2 of
these computers, find the probability distribution for the number of
defectives.

Solution

The probability that has defective is 3/20 = 0.15

So the probability distribution for the number of defectives is

X follows Binomial distribution with n=2 and p=0.15

P(X=x)=2Cx*(0.15^x)*(0.85^(2-x)) for x=0,1,2,