document.write( "Question 866158: A family has 4 children. Let B be the event \"the family has children of both sexes\". Find P(B). \n" ); document.write( "

Algebra.Com's Answer #522188 by Fombitz(32388) $\"\"$ $\"About$

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Let A be the event \"the family has children of only one sex\".
\n" ); document.write( "Let B be the event \"the family has children of both sexes\".
\n" ); document.write( "It's clear that
\n" ); document.write( " $\"P%28A%29%2BP%28B%29=1\"$
\n" ); document.write( "There are 16 possible combinations of sexes from MMMM, MMMF, through, FFFM, FFFF.
\n" ); document.write( "Only two fall into the A category {MMMM,FFFF} so,
\n" ); document.write( " $\"P%28A%29=2%2F16=1%2F8\"$
\n" ); document.write( "So then,
\n" ); document.write( " $\"P%28B%29=1-P%28A%29\"$
\n" ); document.write( " $\"P%28B%29=1-1%2F8\"$
\n" ); document.write( " $\"P%28B%29=7%2F8\"$
\n" ); document.write( " \n" ); document.write( "

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