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 HELPPP i wanna know if i did it right, i got 21% i multiplied 70% and 30% ( 0.70 x 0.30 )

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In a city school, 70% of students have blue eyes, 45% have dark hair, and 30% have blue eyes and dark hair. What is the probability (rounded to the nearest whole percent) that a randomly selected student has dark hair, given that the student has blue eyes?

 

A. 67%
B. 21%
C. 43%
D. 46%

 Mar 29, 2016

1+0 Answers

 #1
avatar+128731 
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This Venn Diagram might help

 

 

 

Notice that 70% have blue eyes....and of these, 30% also have dark hair

 

So,   30/70  of the people who have blue eyes also have dark hair

 

And  30/70  = 3/7  =  about   43%

 

So.....C is the correct answer

 

 

cool cool cool

 Mar 29, 2016

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