document.write( "Question 1189395: Please help me solve this problem!!\r
\n" ); document.write( "\n" ); document.write( ": A book dealer has books in store of which 1/5 were hardcover books . the dealer sold 2/3 of the books , including 3/4 of the hardcover books . what fraction of the unsold books were hardcover books??
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Algebra.Com's Answer #820745 by Theo(13342)\"\" \"About 
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let x = the number of books the dealer had.
\n" ); document.write( "let h = the number of hard cover books.\r
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\n" ); document.write( "\n" ); document.write( "1/5 of the books were hard cover.
\n" ); document.write( "therefore:
\n" ); document.write( "h = 1/5 * x\r
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\n" ); document.write( "\n" ); document.write( "the dealer sold 2/3 of the books that included 3/4 of the hard cover books.\r
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\n" ); document.write( "\n" ); document.write( "this means the dealer sold 3/4 * h.\r
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\n" ); document.write( "\n" ); document.write( "this means the dealer did not sell 1/4 * h.\r
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\n" ); document.write( "\n" ); document.write( "the fraction of the books that were not sold = 1/3 * x.\r
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\n" ); document.write( "\n" ); document.write( "the ratio of the number of hard cover books that were not sold to the number of books that were not sold is (1/4 * h) / (1/3 * x).\r
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\n" ); document.write( "\n" ); document.write( "since h = 1/5 * x, the ratio becomes (1/4 * 1/5 * x) / (1/3 * x).\r
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\n" ); document.write( "\n" ); document.write( "that becomes (1/20 * x) / (1/3 * x).\r
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\n" ); document.write( "\n" ); document.write( "that becomes (1/20) / (1/3) which is equal to (1/20) * 3 which is equal to 3/20.\r
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\n" ); document.write( "\n" ); document.write( "the fraction of the unsold books that were hard cover was 3/20.\r
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\n" ); document.write( "\n" ); document.write( "to test this out, i created an example.
\n" ); document.write( "in the example, i assumed the total number of books was 120.
\n" ); document.write( "since the number of hard cover books was 1/5 * the total number of books, then the number of hard cover books was 24.\r
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\n" ); document.write( "\n" ); document.write( "2/3 of the books were sold, including 3/4 of the hard cover books.\r
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\n" ); document.write( "\n" ); document.write( "what was sold was:
\n" ); document.write( "2/3 * 120 = 80 total books.
\n" ); document.write( "this included 3/4 * 24 = 18 hard cover books.\r
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\n" ); document.write( "\n" ); document.write( "what was not sold was:
\n" ); document.write( "1/3 * 120 = 40 total books.
\n" ); document.write( "this included 1/4 * 24 = 6 hard cover books.\r
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\n" ); document.write( "\n" ); document.write( "the ratio of unsold hard cover books to unsold books was 6/40 = 3/20.\r
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\n" ); document.write( "\n" ); document.write( "this confirms the fraction is correct.\r
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\n" ); document.write( "\n" ); document.write( "your solution is that the fraction of unsold books that were hard cover books is 3/20.\r
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