document.write( "Question 1203559: Let P(A) = P(B) = 1/3 and P(A n B) 1/10, Find the following:
\n" ); document.write( "A) P(B')
\n" ); document.write( "B) P(A u B')
\n" ); document.write( "C) P(B n A')
\n" ); document.write( "D) P(A' u B')
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Algebra.Com's Answer #839216 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "Problem 1\r
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\n" ); document.write( "\n" ); document.write( "Use the complement law of probability
\n" ); document.write( "P(B') = 1 - P(B)
\n" ); document.write( "P(B') = 1 - (1/3)
\n" ); document.write( "P(B') = 2/3\r
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\n" ); document.write( "\n" ); document.write( "---------------------------\r
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\n" ); document.write( "\n" ); document.write( "Problem 2\r
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\n" ); document.write( "\n" ); document.write( "Law of total probability
\n" ); document.write( "P(A) = P(A n B) + P(A n B')
\n" ); document.write( "rearrange it to
\n" ); document.write( "P(A n B') = P(A) - P(A n B)
\n" ); document.write( "Check out this question for more info
\n" ); document.write( "https://www.algebra.com/algebra/homework/Probability-and-statistics/Probability-and-statistics.faq.question.1203558.html
\n" ); document.write( "refer to problem 1 of that link\r
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\n" ); document.write( "\n" ); document.write( "Then,
\n" ); document.write( "P(A u B') = P(A) + P(B') - P(A n B') ...... inclusion-exclusion principle
\n" ); document.write( "P(A u B') = P(A) + P(B') - [P(A) - P(A n B)] ...... use rule mentioned above
\n" ); document.write( "P(A u B') = P(A) + P(B') - P(A) + P(A n B)
\n" ); document.write( "P(A u B') = P(B') + P(A n B)
\n" ); document.write( "P(A u B') = (2/3) + (1/10)
\n" ); document.write( "P(A u B') = (20/30) + (3/30)
\n" ); document.write( "P(A u B') = (20+3)/30
\n" ); document.write( "P(A u B') = 23/30\r
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\n" ); document.write( "\n" ); document.write( "Problem 3\r
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\n" ); document.write( "\n" ); document.write( "Use a similar trick I did in the previous problem to determine that
\n" ); document.write( "P(B n A') = P(B) - P(B n A)
\n" ); document.write( "which is the same as
\n" ); document.write( "P(B n A') = P(B) - P(A n B)\r
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\n" ); document.write( "\n" ); document.write( "Furthermore
\n" ); document.write( "P(B n A') = P(B) - P(A n B)
\n" ); document.write( "P(B n A') = (1/3) - (1/10)
\n" ); document.write( "P(B n A') = (10/30) - (3/30)
\n" ); document.write( "P(B n A') = (10-3)/30
\n" ); document.write( "P(B n A') = 7/30\r
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\n" ); document.write( "\n" ); document.write( "Problem 4\r
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\n" ); document.write( "\n" ); document.write( "P(A' u B') = P( (A n B)' ) ... De Morgans Law
\n" ); document.write( "P(A' u B') = 1 - P(A n B) ... complement law
\n" ); document.write( "P(A' u B') = 1 - (1/10)
\n" ); document.write( "P(A' u B') = (10/10) - (1/10)
\n" ); document.write( "P(A' u B') = (10-1)/10
\n" ); document.write( "P(A' u B') = 9/10
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