Final answer:
The question cannot be answered with the information provided as it lacks the necessary data about the probabilities related to car wash purchases and vacuuming preferences.
Step-by-step explanation:
The question asks for the probability that a randomly selected customer purchases a classic car wash given that they do not vacuum their car. However, the information provided does not specify the necessary data for this particular scenario. To solve a problem like this, one would typically use the concept of conditional probability, which requires data about the joint probability of purchasing a car wash and not vacuuming, as well as the probability of not vacuuming alone.
Without this specific information, it's impossible to give a numerical answer. Yet, if we had the details, the calculation would follow the formula P(A|B) = P(A and B) / P(B), where P(A|B) is the conditional probability of event A given event B, P(A and B) is the joint probability of both events occurring, and P(B) is the probability of event B occurring.