A store owner receives 12 computers:nine are model A and the rest are model B.if two computers are sold at random,find the probability that one of each model is sold.
To find the probability that one of each model is sold, we need to first calculate the total number of possible ways two computers can be sold from the 12 available computers.
The total number of ways to choose two computers from 12 is given by the combination formula:
C(12,2) = 12! / (2!(12-2)!) = 66
Now, let's calculate the number of ways to choose one computer of model A and one computer of model B.
There are 9 computers of model A, so we can choose one from these in C(9,1) = 9 ways.
The remaining 3 computers are of model B, so we can choose one from these in C(3,1) = 3 ways.
So, the total number of ways to choose one of each model is 9 * 3 = 27.
Therefore, the probability of selecting one computer of model A and one computer of model B is:
P(one of each model) = (number of ways to choose one of each model) / (total number of ways to choose two computers)
P(one of each model) = 27 / 66
Simplifying the fraction, we get:
P(one of each model) = 9 / 22