document.write( "Question 1155136: Suppose Set A contains 66 elements and Set B contains 94 elements. If Sets A and B have 1 elements in common, what is the total number elements in either Set A or Set B.
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Algebra.Com's Answer #777704 by ikleyn(52781) $\"\"$ $\"About$

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document.write( "There are  66 + 94 - 1 = 159 elements in the union.    ANSWER\r\n" );
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document.write( "    Every time, when you have an universal set U and two its finite subsets A and B with  n(A) and n(B) elements \r\n" );
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document.write( "    respectively,  the number of elements in their UNION (A U B) is\r\n" );
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document.write( "        n(A U B) = n(A) + n(B) - n(A intersection B),\r\n" );
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document.write( "    where n(A intersection B) is the number of elements in their intersection.\r\n" );
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\n" ); document.write( "\n" ); document.write( "The last equality DESERVES you MEMORIZE it.\r
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\n" ); document.write( "\n" ); document.write( "It is one of the basic equalities (identities) in elementary Set theory.\r
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\n" ); document.write( "\n" ); document.write( "See the lesson\r
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