document.write( "Question 456890: An executive invests $28,000, some at 7% and some at 4% annual interest. If he receives an annual return of $1720, how much is invested at each rate?
\n" ); document.write( "at 7% interest
\n" ); document.write( "at 4% interest\r
\n" ); document.write( "\n" ); document.write( "please help me solve this. I would be greatly appreciated \n" ); document.write( "
Algebra.Com's Answer #313499 by mananth(16949)\"\" \"About 
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\n" ); document.write( "Investment I 7.00% per annum $x
\n" ); document.write( "Investment II 4.00% per annum $y
\n" ); document.write( "x+y=28000 ------------------------1
\n" ); document.write( "7.00%x+4.00%y=$1,720.00
\n" ); document.write( "Multiply by 100
\n" ); document.write( "7x+4y=$172,000.00 --------2
\n" ); document.write( "Multiply (1) by -7
\n" ); document.write( "we get
\n" ); document.write( "-7x-7y= -196000.00
\n" ); document.write( "Add this to (2)
\n" ); document.write( "-3y=-$24,000.00
\n" ); document.write( "divide by -3
\n" ); document.write( "y=$8,000.00 investment at 4.00%
\n" ); document.write( "Balance $20,000.00 investment at 7.00%\r
\n" ); document.write( "\n" ); document.write( "CHECK
\n" ); document.write( "20000 @ 7%=$1,400.00
\n" ); document.write( "8000 @ 4% = $320.00
\n" ); document.write( "TOTAL Interest $1,720.00\r
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