document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=275322>Question 275322</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A display of cans on a grocery shelf consists of 20 cans on the bottom, 18 cans in the next row, and so on in an arithmetic sequence, until the top row has 4 cans. How many cans, in total, are in the display?\r<BR>\n" );
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document.write( "please use the equation needed so i know how to do it.<BR>\n" );
document.write( "thank you:) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #200824 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=200824\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A display of cans on a grocery shelf consists of 20 cans on the bottom, 18 cans in the next row, and so on in an arithmetic sequence, until the top row has 4 cans. How many cans, in total, are in the display? <BR>\n" );
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document.write( "20 + 18 + ... + 6 + 4<BR>\n" );
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document.write( "a = 20 ; d = -2 ; n = ?<BR>\n" );
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document.write( "4 = 20 + (n-1)(-2)<BR>\n" );
document.write( "-16 = (n-1)(-2)<BR>\n" );
document.write( "n-1 = 8<BR>\n" );
document.write( "n = 9<BR>\n" );
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document.write( "S(9) = (9/2)(20+4)<BR>\n" );
document.write( "S(9) = 4.5*24<BR>\n" );
document.write( "S(9) = 108<BR>\n" );
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document.write( "cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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