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If 32% of the residents of Toronto wear glasses, 11% have green eyes and wear glasses, and 45% have

neither green eyes nor wear glasses, what is the probability that a randomly selected resident has green
eyes? (3

User GEMI
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1 Answer

3 votes

Answer: 77.28

Explanation:

To solve this problem, we can use the formula:

P(G) = P(G ∩ NG') + P(G ∩ NG)

where P(G) is the probability that a resident has green eyes, P(G ∩ NG') is the probability that a resident has green eyes and does not wear glasses, and P(G ∩ NG) is the probability that a resident has green eyes and wears glasses. NG' represents the complement of wearing glasses, i.e. not wearing glasses.

We are given that 32% of the residents wear glasses, so the probability of not wearing glasses (NG) is:

NG = 1 - 0.32 = 0.68

We are also given that 11% have green eyes and wear glasses:

P(G ∩ NG) = 0.11

We can use this information to find the probability of having green eyes and not wearing glasses:

P(G ∩ NG') = P(G) - P(G ∩ NG) = 0.11 - P(G ∩ NG')

We are also given that 45% of the residents have neither green eyes nor wear glasses:

P(NG' ∩ NG) = 0.45

We can use this information to find the probability of not having green eyes and wearing glasses:

P(NG ∩ G') = P(G' ∩ NG) = 0.45

We can now set up a system of equations to solve for P(G) and P(G ∩ NG'):

P(G ∩ NG') = P(G) - P(G ∩ NG)

P(G' ∩ NG) = P(NG) - P(NG' ∩ NG)

Substituting the values we have:

P(G ∩ NG') = P(G) - 0.11

0.45 = 0.68P(G' ∩ NG)

Solving for P(G' ∩ NG), we get:

P(G' ∩ NG) = 0.45/0.68 = 0.6628

Substituting this value into the first equation, we get:

P(G ∩ NG') = P(G) - 0.11

P(G) = P(G ∩ NG') + 0.11

P(G) = 0.6628 + 0.11

P(G) = 0.7728

Therefore, the probability that a randomly selected resident of Toronto has green eyes is approximately 0.7728 or 77.28%.

User Giuseppe De Marco
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