What is the probability of a defective paint job?

113 Views Asked by At

After the initial production run of a new style of a steel desk, a quality control technician found that 40% of the desks had an alignment problem and 10% had both a defective paint job and an alignment problem. If a desk is randomly selected from this run and it has an alignment problem, what is the probability that it also has a defective paint job? (Let "A" be the event "having an alignment problem" and D be the event "having a defective paint job")

1

There are 1 best solutions below

3
On BEST ANSWER

Think of the different issues as an event that has a certain probability. Let $A$ be the event that there is an alignment issue, and $B$ be the event that there is a defective paint job.

The question provides you with two facts:

(1) The probability that there is an alignment issue is 40%.

$P(A)=0.4$

(2) The probability that there is both an alignment issue, and a defective paint job is 10%

$P(A\cap B)=0.1$

The question is asking a fundamental property of the probability of the event $B$ happening given that $A$ has occurred. Since $A$ has occurred, you no longer need to consider the case in which there is no alignment issue. This narrows the scope of possibilities.