document.write( "Question 443601: A quiz consists of 20 multiple-choice questions, each with 5 possible answers. For someone who makes random guesses for all of the answers, find the probability of passing if the minimum passing grade is 70 %. \n" ); document.write( "

Algebra.Com's Answer #306051 by ewatrrr(24785) $\"\"$ $\"About$

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document.write( "Hi
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document.write( "A quiz consists of 20 multiple-choice questions, each with 5 possible answers
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document.write( " P(passing) if the minimum passing grade is 70 %. |that is, 14 or more correct
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document.write( "Note: The probability of x successes in n trials is: 
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document.write( "P = nCx*  where p and q are the probabilities of success and failure respectively. 
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document.write( "In this case p = 1/5 = .2 and q = .8
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document.write( "nCx = 
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document.write( "For example:
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document.write( " P(x = 14) =  30C14(.2)^14(.8)^6 = 38,760(.2)^14(.8)^6 = .0000016647
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document.write( " P(x ≥ 14) = P(14)+P(15)+P(16)+P(17)+P(18)+P(19)+P(20) = .000001845 \n" );
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