Final answer:
The expected number of car inspections before encountering a failed inspection, with a failure rate of 20%, is calculated to be 5 using the geometric distribution's expected value formula.
Step-by-step explanation:
The subject of the question involves calculating the expected number of car inspections before a car fails, given a 20% failure rate. This is a probability question that can be solved using the concept of geometric distribution. The expected value (E) for a geometrically distributed random variable is given by the formula E = 1/p, where p is the probability of success (in this case, the probability of a car failing the inspection).
Here, we are given that p = 0.20 (20%). So, the expected number of car inspections before one fails is E = 1/0.20 = 5. Therefore, on average, one would expect 5 cars to be inspected before encountering a failure.