TITLE: Conditional multiplication probability
QUESTION [0 upvotes]: In a city, 40% of the inhabitants have one eye, 20% have black skin and 15% have both black skin and one eye. A person is randomly selected from the city.
a.  If he has black skin, what is the probability he also have one eye?
b.  If he has one eye, what is the probability he does not have black skin?
c. If he does not have black skin,  what is the probability he has one eye?

REPLY [0 votes]: In a city, 40% of the inhabitants have one eye, 20% have black skin and 15% have both black skin and one eye. A person is randomly selected from the city.

What you know: $\mathsf P(E)=0.4\\\mathsf P(B)=0.20\\\hspace{-4.5ex}\mathsf P(E\cap B)=0.15$

a.  If he has black skin, what is the probability he also have one eye?

You seek: $\mathsf P(E\mid B)$.   Simply apply the definition of conditional probability.

b.  If he has one eye, what is the probability he does not have black skin?
c. If he does not have black skin,  what is the probability he has one eye?

And similar.  Also use the rule of a complement's probability.
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