document.write( "Question 487208: I need help with an investment problem: Tom made an extra $5000 last year from a part-time job. He invested part of the money at 6% and the rest at 8%. He made a total of $380 in interest. How much was invested at 8%? \n" ); document.write( "

Algebra.Com's Answer #332996 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+a+\"$ = amount invested @ 6%
\n" ); document.write( "Let $\"+b+\"$ = amount invested @ 8%
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+a+%2B+b+=+5000+\"$
\n" ); document.write( "(2) $\"+.06a+%2B+.08b+=+380+\"$
\n" ); document.write( "----------------------
\n" ); document.write( "Multiply both sides of (2) by $\"+100+\"$
\n" ); document.write( "Then multiply both sides of (1) by $\"+6+\"$
\n" ); document.write( "Then subtract (1) from (2)
\n" ); document.write( "(2) $\"+6a+%2B+8b+=+38000+\"$
\n" ); document.write( "(1) $\"+-6a+-+6b+=+-30000+\"$
\n" ); document.write( " $\"+2b+=+8000+\"$
\n" ); document.write( " $\"+b+=+4000+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+a+%2B+b+=+5000+\"$
\n" ); document.write( "(1) $\"+a+%2B+4000+=+5000+\"$
\n" ); document.write( "(1) $\"+a+=+1000+\"$
\n" ); document.write( "$4,000 was invested @ 8%
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+.06a+%2B+.08b+=+380+\"$
\n" ); document.write( "(2) $\"+.06%2A1000+%2B+.08%2A4000+=+380+\"$
\n" ); document.write( "(2) $\"+60+%2B+320+=+380+\"$
\n" ); document.write( "(2) $\"+380+=+380+\"$
\n" ); document.write( "OK \n" ); document.write( "

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