document.write( "Question 567012: William opened two investment accounts for his grandson’s college fund. The first year, these investments, which totaled $18,000, yielded $831 in simple interest. Part of the money was invested at 5.5% and the rest at 4%. How much was invested at each rate? \n" ); document.write( "
Algebra.Com's Answer #366425 by mananth(16946)\"\" \"About 
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Investment Part I 5.50% per annum ----x
\n" ); document.write( "Investment part II 4.00% per annum ----y
\n" ); document.write( "The sum of the investments is $18,000.00
\n" ); document.write( "The sum of individual interests = $831.00
\n" ); document.write( "x+y 18000 ------------------------1
\n" ); document.write( "5.50%x +4.00%y = $831.00
\n" ); document.write( "Multiply by 100
\n" ); document.write( "5.5x + 4y = $83,100.00 --------2
\n" ); document.write( "
\n" ); document.write( "Multiply (1) by -5.5
\n" ); document.write( "we get
\n" ); document.write( "
\n" ); document.write( "-5.5x -5.5y =-99000.00
\n" ); document.write( "
\n" ); document.write( "Add this to (2)
\n" ); document.write( "
\n" ); document.write( "0x -1.5y =-$15,900.00
\n" ); document.write( "
\n" ); document.write( "divide by-1.5
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\n" ); document.write( "y = $10,600.00 investment at 4.00%
\n" ); document.write( "Balance $7,400.00 investment at 5.50%
\n" ); document.write( "CHECK
\n" ); document.write( "$7,400.00 @ 5.50% $407.00
\n" ); document.write( "$10,600.00 @ 4.00% $424.00
\n" ); document.write( "Total -------------------- $831.00
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