document.write( "Question 1134692: In a colony all families have at least two child.The probability that a randomly chosen family from this colony has exactly k children is
\n" ); document.write( "4/5*(1/5)^k-2;k=2,3... A child is either a male or a female with equal
\n" ); document.write( "probability.What will be the probability that a randomly selected family has
\n" ); document.write( "EXACTLY 2 boys? \n" ); document.write( "

Algebra.Com's Answer #752148 by Edwin McCravy(20060) $\"\"$ $\"About$

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In a colony all families have at least two child.The probability that a randomly chosen family from this colony has exactly k children is
\n" ); document.write( "4/5*(1/5)^(k-2);k=2,3... A child is either a male or a female with equal
\n" ); document.write( "probability.What will be the probability that a randomly selected family has
\n" ); document.write( "EXACTLY 2 boys?
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document.write( "The probability of having EXACTLY 2 children is found by substituting 2 for k\r\n" );
document.write( "in the formula\r\n" );
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document.write( "4/5*(1/5)^(2-2) = 4/5*(1/5)^0 = 45*1 = 4/5\r\n" );
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document.write( "There are 4 ways to have EXACTLY 2 children, BB, BG, GB, and GG.  So we must divide 4/5 by 4.\r\n" );
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document.write( "Answer: 1/5\r\n" );
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document.write( "[Note: Maybe you wonder why we didn't divide by 2 instead of 4.  That's\r\n" );
document.write( "because there are just as many of one of the 4 cases as any of the others.]\r\n" );
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document.write( "Edwin

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