document.write( "Question 64817: Walt made an extra $10,0000 last year from a part-time job. He invested part of the money at 8% and the rest at 7%. He made a total of $760 in interest. How much was invested at 7%? \n" ); document.write( "
Algebra.Com's Answer #45339 by tutorcecilia(2152)\"\" \"About 
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Use the standard equation of a line:
\n" ); document.write( "Ax+By=C
\n" ); document.write( "and
\n" ); document.write( "x+y=C
\n" ); document.write( "So, x+(C-x)=C
\n" ); document.write( ".
\n" ); document.write( "7%x+8%y=760
\n" ); document.write( "So, .07x+.08(10,000-x)=760 [change percentages to decimals]
\n" ); document.write( ".07x+800-.08x=760 [solve for x]
\n" ); document.write( "-.01x=-800+760
\n" ); document.write( "-.01x=-40
\n" ); document.write( "x=-40/-.01
\n" ); document.write( "x=$4,000 invested at 7%
\n" ); document.write( "$10,000-4,000=$6000 invested at 8%
\n" ); document.write( ".
\n" ); document.write( "check by plugging in all of the values back into the original equation:
\n" ); document.write( ".07(4,000)+.08(10,000-(4,000))=760
\n" ); document.write( "760=760 [checks out]\r
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