document.write( "Question 888679: All the chairs in the hall were arranged in rows of 15. When the chairs were arranged in rows of 10, there were 4 more rows and 5 chairs leftover. How many rows of 15 chairs were there in the hall at first? \n" ); document.write( "
Algebra.Com's Answer #537596 by Edwin McCravy(20059)\"\" \"About 
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The question is:\r\n" );
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\n" ); document.write( "How many rows of 15 chairs were there in the hall at first?
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document.write( "So we let N = the number of rows of 15 chairs there were in the hall at first.\r\n" );
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\n" ); document.write( "All the chairs in the hall were arranged in rows of 15.
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document.write( "Therefore there were 15N chairs.\r\n" );
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\n" ); document.write( "When the chairs were arranged in rows of 10, there were 4 more rows,
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document.write( "that's (N+4) rows of 10 each, or 10(N+4) chairs in the rows\r\n" );
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\n" ); document.write( "and 5 chairs left over,
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document.write( "so we add 5 more to that, and that gives \r\n" );
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document.write( "10(N+4)+5 \r\n" );
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document.write( "chairs after they were rearranged in rows of 10.  So the number \r\n" );
document.write( "of chairs when they were arranged in rows of 15 must equal the \r\n" );
document.write( "number of chairs when they were arranged in rows of 10. So the \r\n" );
document.write( "equation is:\r\n" );
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document.write( "15N = 10(N+4)+5\r\n" );
document.write( "15N = 10N+40+5\r\n" );
document.write( "15N = 10N+45\r\n" );
document.write( " 5N = 45\r\n" );
document.write( "  N = 9\r\n" );
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document.write( "Checking:\r\n" );
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document.write( "There were 9 row of 15 each in the beginning, which is 9×15 or 135 chairs\r\n" );
document.write( "Then when they were arranged in 9+4 or 13 rows of 10 each, those rows \r\n" );
document.write( "contained 13×10 or 130 chairs, and the 5 left over makes 135.  So it checks.\r\n" );
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document.write( "Edwin

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