I can easily solve a problem if the probabilities are already defined in the question.. such as P(A|B)(adsbygoogle = window.adsbygoogle || []).push({});

But I always get confused about how to actually define the probability from an application exercise.

E.g..

Market research shows that (A)75% if customers want text messages on their phone, (B)80% want photo capability, (AnB)65% want both.

What are the probabilities that a person who wants text messages also wants photo capability?

Would the formula be

P(A|B)=answer

or

P(B|A)=answer

Also could you please explain in detail how I would know which letter goes first since I always get it confused.

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# Conditional probability help

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