# Find the probability of using debit card Our professor gave this question as assignment, My question is does this question have all information needed to solve it? I asked her and she said it has all information but still I cannot figure out how I can solve it with just knowing the probability of using debit card in supermarket. Can someone please provide me a tip on how I can solve this question with this information or is it solvable? According to a recent Interact survey, 28% of consumers use their debit cards in supermarkets. Find the probability that they use debit cards in only other stores or not at all.

Find the probability of using debit card
Our professor gave this question as assignment, My question is does this question have all information needed to solve it? I asked her and she said it has all information but still I cannot figure out how I can solve it with just knowing the probability of using debit card in supermarket. Can someone please provide me a tip on how I can solve this question with this information or is it solvable?
According to a recent Interact survey, 28% of consumers use their debit cards in supermarkets. Find the probability that they use debit cards in only other stores or not at all.
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Remington Wells
The intended answer is mostly likely 72%. This is because to say that a consumer uses his/her debit cards "in only other stores or not at all" is logically equivalent to saying that he/she does not use his/her debit cards in supermarkets. So if 28% of consumers do use their debit cards in supermarkets, then 72% do not.
That said, the problem strikes me as not well worded. In giving the answer of 72%, I am assuming that what's meant by "the probability that they use debit cards..." is the probability that a randomly selected individual consumer uses his/her debit cards only in other stores or not at all. As stated, however, it's asking about the probability that an entire collection of consumers use their debit cards in a certain way.
Whether you read the "they" as referring to the entire set of consumers, or just to the 28% who use them at supermarkets (as quasi's answer does), the answer is 0. It's possible the person writing the question really meant it this way, as quasi suggests; I think it's more likely they were just a bit sloppy in their wording. I know I sometimes am.