document.write( "Question 857412: There are 9 black balls and 6 red balls in an urn. if 3 balls are drawn without replacement, what is the probability that no more than 1 black ball is drawn? \n" ); document.write( "

Algebra.Com's Answer #517313 by Edwin McCravy(20055) $\"\"$ $\"About$

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document.write( "To get the numerator of the probability:\r\n" );
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document.write( "Two cases: \r\n" );
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document.write( "Case 1: choose 0 black balls and all 3 red balls: \r\n" );
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document.write( "Choose all three red balls C(6,3) = 20 ways\r\n" );
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document.write( "Case 2: choose 1 black ball and 2 red balls:\r\n" );
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document.write( "Choose the black ball C(9,1) = 9 ways\r\n" );
document.write( "Choose the 2 red balls C(6,2) = 15 ways\r\n" );
document.write( "That's 9×15 = 135 ways\r\n" );
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document.write( "That's 20 + 135 = 155 ways.\r\n" );
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document.write( "To get the denominator:\r\n" );
document.write( "Choose any 3 balls from the 15 in C(15,3) = 455 ways.\r\n" );
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document.write( "Probability that no more than 1 black ball is drawn =  = ,\r\n" );
document.write( "approximately 34% of the time.\r\n" );
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document.write( "Edwin

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