document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1134278>Question 1134278</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The sixth & eleventh terms of a linear sequence are respectively 23 & 48. Calculate the sum of the first twenty terms  </SPAN>\n" );
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document.write( "The 11th term is the 6th term plus the common difference 5 times, so the common difference is<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%2848-23%29%2F5+=+25%2F5+=+5 ALIGN=MIDDLE  ALT=\"%2848-23%29%2F5+=+25%2F5+=+5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "The sum of the first 20 terms of the sequence is 20 times the average of all the terms; the average of all the terms is the average of the middle two terms -- the 10th and 11th terms.  Since the 11th term is 48 and the common difference is 5, the 10th term is 43; then the average of the terms in the sequence is (43+48)/2 = 91/2.<br><BR>\n" );
document.write( "And so the sum of the first 20 terms is<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20%2891%2F2%29+=+10%2A91+=+910 ALIGN=MIDDLE  ALT=\"20%2891%2F2%29+=+10%2A91+=+910\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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