document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=843209>Question 843209</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the sum of the fourth and twelfth term of an A.P is 120.what is the sum of the first 15 terms of the A.p<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #516258 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=516258\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> an = a + (n - 1)d<BR>\n" );
document.write( "a4 = a + 3d<BR>\n" );
document.write( "a12 = a + 11d<BR>\n" );
document.write( "120=2a+14d\r<BR>\n" );
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document.write( "S = ½(2a + (n-1)d)n<BR>\n" );
document.write( "S = ½(2a + (14)d)15<BR>\n" );
document.write( "S = ½(120)15<BR>\n" );
document.write( "S=900 </SPAN>\n" );
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