document.write( "Question 1124696: The sum of first 3 integers in an Arithmetic progression is 36. The sum of the next 3 integers is 72. What is the common difference between the terms? \n" ); document.write( "

Algebra.Com's Answer #741021 by math_helper(2461) $\"\"$ $\"About$

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\n" ); document.write( "(1) $\"+a%5B1%5D+%2B+%28a%5B1%5D%2Bd%29+%2B+%28a%5B1%5D%2B2d%29+=+36+\"$
\n" ); document.write( "(2) $\"+%28a%5B1%5D%2B3d%29+%2B+%28a%5B1%5D%2B4d%29+%2B+%28a%5B1%5D%2B5d%29+=+72+\"$ \r
\n" ); document.write( "\n" ); document.write( "(1) ==> $\"3a%5B1%5D+%2B+3d+=+36+\"$
\n" ); document.write( "(2) ==> $\"3a%5B1%5D+%2B+12d+=+72+\"$ \r
\n" ); document.write( "\n" ); document.write( "Subtract (1) from (2):
\n" ); document.write( " $\"+9d+=+36+\"$ Ч> $\"+highlight%28+d+=+4+%29+\"$ \r
\n" ); document.write( "\n" ); document.write( "ЧЧЧЧЧЧЧЧ
\n" ); document.write( "Another approach:
\n" ); document.write( " In the first group of three, the average value is 36/3 = 12 (= middle value, $\"a%5B2%5D\"$ )
\n" ); document.write( " In the 2nd group of three, the average value is 72/3 = 24 (= middle value, $\"a%5B5%5D\"$ )\r
\n" ); document.write( "\n" ); document.write( "Since $\"+a%5B5%5D+=+a%5B2%5D+%2B+3d+\"$ : 24 = 12 + 3d Ч> 3d = 12 Ч> d = 4\r
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