SOLUTION: Mr. Johnson has nine brown-eyed and three blue-eyed brunettes in his fourth grade class. He also has two blue-eyed and three brown-eyed children with black hair. A child is selecte

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Question 1135844: Mr. Johnson has nine brown-eyed and three blue-eyed brunettes in his fourth grade class. He also has two blue-eyed and three brown-eyed children with black hair. A child is selected at random. What is the probability that the child has brown eyes given that he or she is a brunette?
Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13200)   (Show Source): You can put this solution on YOUR website!


The brunettes are 9 with brown eyes and 3 with blue eyes, a total of 12. If a randomly chosen child is brunette, the probability that it has brown eyes is 9/12, or 3/4.
Answer by ikleyn(52781)   (Show Source): You can put this solution on YOUR website!
.
There are two (TWO) groups of students under the consideration.


First group (let's call it A) consists of nine brown-eyed and three blue-eyed brunettes.


Second group (let's call it B) consists of two blue-eyed and three brown-eyed children with black hair.


Since the chosen student is a brunette, it means that he (or she) was chosen among the group A.


The probability to choose a child with brown eyes among the group A is   =  =  = 0.75 = 75%.   ANSWER

Solved.


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