document.write( "Question 30970: Joe has $40,000 to invest. He invests part of it at 5%, one-fourth of this amount at 6%, and the rest of the money at 7%. His total annual interest income is $2,530. Find the amount invested at each rate. \n" ); document.write( "

Algebra.Com's Answer #17724 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\".05+%2A+x+%2B+.25+%2A+.06+%2A+x+%2B+.07+%2A+%284%2A10%5E4+-+%285%2F4%29%2Ax%29+=+2530\"$
\n" ); document.write( "note that (5/4)*x is (1 + 1/4)*x or x + (1/4)*x which is the amounts
\n" ); document.write( "that are NOT invested at 7%, so 40000 - (5/4)*x is the amount invested
\n" ); document.write( "at 7%
\n" ); document.write( " $\".05+%2A+x+%2B+.25+%2A+.06+%2A+x+%2B+.07+%2A+4%2A10%5E4+-+.07+%2A+%285%2F4%29%2Ax+=+2530\"$
\n" ); document.write( " $\".05+%2A+x+%2B+.015+%2A+x+%2B+.07+%2A+4%2A10%5E4+-+.0875+%2A+x+=+2530\"$
\n" ); document.write( " $\".065+%2A+x+%2B+.07+%2A+4%2A10%5E4+-+.0875+%2A+x+=+2530\"$
\n" ); document.write( " $\".065+%2A+x+%2B+2800+-+.0875+%2A+x+=+2530\"$
\n" ); document.write( " $\"-.0225+%2A+x+%2B+2800++=+2530\"$
\n" ); document.write( " $\"-.0225+%2A+x++=+2530+-+2800+\"$
\n" ); document.write( " $\"-.0225+%2A+x++=+-270\"$
\n" ); document.write( " $\"+x+=+12000\"$
\n" ); document.write( " $\"%281%2F4%29+%2A+x+=+3000\"$
\n" ); document.write( " $\"4+%2A+10%5E4+-+%28%285%2F4%29+%2A+x%29+=+25000\"$
\n" ); document.write( "check
\n" ); document.write( "

\r
\n" ); document.write( "\n" ); document.write( " $\"600+%2B+180+%2B+.07+%2A+%2825000%29+=+2530\"$
\n" ); document.write( " $\"780+%2B+1750+=+2530\"$
\n" ); document.write( " $\"2530+=+2530\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

\n" );