document.write( "Question 1187121: Given that S=7a+b+7c and also S=6a+8b+6c, where 51\n" ); document.write( "
Algebra.Com's Answer #818066 by greenestamps(13200)\"\" \"About 
You can put this solution on YOUR website!


\n" ); document.write( "\"S+=+7a%2Bb%2B7c\" [1]
\n" ); document.write( "\"S+=+6a%2B8b%2B6c\" [2]

\n" ); document.write( "Subtract [2] from [1]:

\n" ); document.write( "\"a-7b%2Bc+=+0\"
\n" ); document.write( "\"a%2Bc+=+7b\"
\n" ); document.write( "\"b+=+%28a%2Bc%29%2F7\" [3]

\n" ); document.write( "Substitute [3] in [1]:

\n" ); document.write( "

\n" ); document.write( "We know a, b, and c are integers, so S is an integer. From the last equation, we also know that S is a multiple of 50, and (a+c) is a multiple of 7.

\n" ); document.write( "We also know that S is between 51 and 149. The only multiple of 50 between 51 and 149 is 100. So

\n" ); document.write( "\"S+=+100+=+50%28%28a%2Bc%29%2F7%29\"
\n" ); document.write( "\"%28a%2Bc%29%2F7=2\"
\n" ); document.write( "\"a%2Bc=14\" [4]

\n" ); document.write( "Substitute [4] in [3]:

\n" ); document.write( "\"b+=+14%2F2+=+7\" [5]

\n" ); document.write( "Combine [4] and [5] to get the answer.

\n" ); document.write( "ANSWER: a+b+c = 14+2 = 16 -- answer choice C

\n" ); document.write( "
\n" ); document.write( "
\n" );