document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=639176>Question 639176</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What is the sum of a 30–term arithmetic sequence where the first term is 73 and the last term is –101? </SPAN>\n" );
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document.write( "The formula is Sn = (n*(a1 + an))/2\r<BR>\n" );
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document.write( "In this case,\r<BR>\n" );
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document.write( "a1 = 73\r<BR>\n" );
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document.write( "an = -101\r<BR>\n" );
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document.write( "n =  30\r<BR>\n" );
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document.write( "Plug all this into the formula above to get\r<BR>\n" );
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document.write( "Sn = (n*(a1 + an))/2\r<BR>\n" );
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document.write( "Sn = (30*(73 + -101))/2\r<BR>\n" );
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document.write( "Sn = (30*(-28))/2\r<BR>\n" );
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document.write( "Sn = (-840)/2\r<BR>\n" );
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document.write( "Sn = -420\r<BR>\n" );
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document.write( "So the answer is <font color=\"red\">-420</font> </SPAN>\n" );
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