document.write( "Question 1124731: the first term of an A.P is 7,the last term is 70 and sum is 385.find the number of terms in the series
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Algebra.Com's Answer #741040 by greenestamps(13200) $\"\"$ $\"About$

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\n" ); document.write( "The sum of an arithmetic progression is the number of terms, multiplied by the average of the first and last terms:

\n" ); document.write( " $\"S+=+n%28%28a%281%29%2Ba%28n%29%29%2F2%29\"$

\n" ); document.write( "Plug in the given information:

\n" ); document.write( " $\"385+=+n%28%287%2B70%29%2F2%29\"$
\n" ); document.write( " $\"770+=+77n\"$
\n" ); document.write( " $\"n+=+10\"$

\n" ); document.write( "There are 10 terms in the A. P. \n" ); document.write( "

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