Final answer:
The probability that the shirt Stanley chooses is not blue is 40%, given that the probability the shirt is blue is 60%.
Step-by-step explanation:
The question inquires about the probability that a shirt chosen at random from Stanley's wardrobe is not blue given that the probability it is blue is 60%. To find the probability that the shirt is not blue, we subtract the given probability that the shirt is blue from the total probability, which is always 100%. Since probabilities must sum up to 100%, if the chance of the shirt being blue is 60%, then the chance of it not being blue is 100% - 60% = 40%.