document.write( "Question 933569: we have to arrange chairs for the audience a in the first row we can place 20 chairs in the next 22 chairs 2 chairs can be added to each row than the previous one we have to arrange 50 so how many chairs are needed WE HAVE TO USE AP FORMULA
\n" ); document.write( " (arithmetic progression)\r
\n" ); document.write( "\n" ); document.write( "so how many chairs will be in the 25th row?\r
\n" ); document.write( "\n" ); document.write( "with thousand how many perfect rows can you make? \r
\n" ); document.write( "\n" ); document.write( "how many chairs will be in the last row? \r
\n" ); document.write( "\n" ); document.write( "what are the difference in the number of chairs for arranging 25 rows and 50 rows? \r
\n" ); document.write( "\n" ); document.write( "in which row 50 chairs will exist? \r
\n" ); document.write( "\n" ); document.write( "will you be able to make perfect rows with thousand chairs? if not how many chairs are needed to make the row perfect?\r
\n" ); document.write( "\n" ); document.write( "if you need to make 2 more rows how more chairs are needed?
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Algebra.Com's Answer #566916 by MathLover1(20849)\"\" \"About 
You can put this solution on YOUR website!
# of chairs in rows: 20, 22,24,26,28,30,32,34,36,38,40,42,44,46,48,50\r
\n" ); document.write( "\n" ); document.write( "difference \"d=2\"
\n" ); document.write( "\"a%5B1%5D=20\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D+=+a%5B1%5D+%2B+%28n-1%29d\"\r
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\n" ); document.write( "\n" ); document.write( "a.
\n" ); document.write( " how many chairs will be in the 25th row?\r
\n" ); document.write( "\n" ); document.write( "\"a%5B25+%5D=+20+%2B+%2825-1%292\"\r
\n" ); document.write( "\n" ); document.write( "\"+a%5B25+%5D=20%2B50-2\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B25+%5D=68\"...chairs will be in the 25th row\r
\n" ); document.write( "\n" ); document.write( "b.
\n" ); document.write( "with \"1000\" chairs how many perfect rows can you make\r
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\n" ); document.write( "\n" ); document.write( " \"1000=+20+%2B+%28n-1%292\"
\n" ); document.write( " \"1000-20+=+%28n-1%292\"
\n" ); document.write( "\"980+=+%28n-1%292\"
\n" ); document.write( "\"980+%2F2=+%28n-1%29\"
\n" ); document.write( "\"490=+n+-1\"
\n" ); document.write( "\"491=+n\" .....# of rows you can make, since \"491\" is NOT a perfect number, \r
\n" ); document.write( "\n" ); document.write( "the only perfect numbers between \"1\" and \"1000\" are \"6\", \"28\", \"496\"; since \"496%3E491\" , with \"1000\" chairs you can make only \"two\" perfect rows which are rows \"6\" and\"28\"\r
\n" ); document.write( "\n" ); document.write( "c.\r
\n" ); document.write( "\n" ); document.write( "how many chairs will be in the last row?
\n" ); document.write( " the last row is \"a%5Bn%5D\":\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn+%5D=+20+%2B+%28n-1%292\" ...# chairs in the last row\r
\n" ); document.write( "\n" ); document.write( "d.\r
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\n" ); document.write( "\n" ); document.write( "what are the difference in the number of chairs for arranging 25 rows and 50 rows?
\n" ); document.write( "\"a%5B25+%5D=68\"...chairs will be in the 25th row\r
\n" ); document.write( "\n" ); document.write( "\"a%5B50+%5D=+20+%2B+%2850-1%292\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B50+%5D=+20+%2B+%2849%292\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B50+%5D=+20+%2B+98\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B50+%5D=+118\"\r
\n" ); document.write( "\n" ); document.write( " the difference in the number of chairs for arranging \"25\" rows and \"50\" rows is \"118-68=50\"\r
\n" ); document.write( "\n" ); document.write( "or, since the difference in the number of chairs for arranging between two rows is 2 chairs, then
\n" ); document.write( "between \"25\" rows and \"50\" will be \"25%2A2=50\"\r
\n" ); document.write( "\n" ); document.write( "e.
\n" ); document.write( "in which row \"50\" chairs will exist? \r
\n" ); document.write( "\n" ); document.write( "\"50+=+20+%2B+%28n-1%292\"\r
\n" ); document.write( "\n" ); document.write( "\"50+-+20+=+%28n-1%292\"\r
\n" ); document.write( "\n" ); document.write( "\"30%2F2+=+%28n-1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"15%2B1=+n\"\r
\n" ); document.write( "\n" ); document.write( "\"n=16\" .....row in which \"50\" chairs will exist\r
\n" ); document.write( "\n" ); document.write( "f.
\n" ); document.write( "will you be able to make perfect rows with thousand chairs? if not how many chairs are needed to make the row perfect? \r
\n" ); document.write( "\n" ); document.write( "from c. we know that \r
\n" ); document.write( "\n" ); document.write( "\"a%5B491+%5D=1000+\" and \"491\" is not perfect row because \"491\" is NOT a perfect number
\n" ); document.write( "first perfect number is \"n=496\"(see b.); so we need 5more rows or 10 more chairs
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\n" ); document.write( "\"a%5B496%5D=+20+%2B+%28496-1%292\"
\n" ); document.write( "\"a%5B496%5D=20+%2B%28495%292\"
\n" ); document.write( "\"a%5B496+%5D-100=20%2B990\"
\n" ); document.write( "\"a%5B496+%5D=1010\" \r
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\n" ); document.write( "\n" ); document.write( "g.\r
\n" ); document.write( "\n" ); document.write( "if you need to add \"2\" more rows you will have \"498\" rows\r
\n" ); document.write( "\n" ); document.write( "as given,for each additional row you need \"2\" more chair; so, to make \"2\" more rows you will need \"4\" more chairs to row \"496\" which is \"1010\"; so, we will have \"1014\" chairs in row # \"498\"\r
\n" ); document.write( "\n" ); document.write( "check:
\n" ); document.write( "\"1014=+20+%2B+%28n-1%292\"\r
\n" ); document.write( "\n" ); document.write( "\"1014=+20+%2B+%28n-1%292\"\r
\n" ); document.write( "\n" ); document.write( "\"1014-20+=2n-2+\"\r
\n" ); document.write( "\n" ); document.write( "\"994%2B2=2n\"\r
\n" ); document.write( "\n" ); document.write( "\"996=2n\"\r
\n" ); document.write( "\n" ); document.write( "\"996%2F2=n\"\r
\n" ); document.write( "\n" ); document.write( "\"n=498\"...so, we got a row number \"498\"
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