Answer:
The probability is
Step-by-step explanation:
Let assume that the number of computer produced by factory C is k = 1
So From the question we are told that
The number produced by factory A is 4k = 4
The number produced by factory B is 7k = 7
The probability of defective computers from A is
The probability of defective computers from B is
The probability of defective computers from C is
Now the probability of factory A producing a defective computer out of the 4 computers produced is
substituting values
The probability of factory B producing a defective computer out of the 7 computers produced is
substituting values
The probability of factory C producing a defective computer out of the 1 computer produced is
substituting values
So the probability that the a computer produced from the three factory will be defective is
substituting values
Now the probability that the defective computer is produced from factory A is