document.write( "Question 585573: 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 #373438 by mananth(16949) $\"\"$ $\"About$

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part I 5.50% per annum---x
\n" ); document.write( "part II 4.00% per annum---y
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\n" ); document.write( "x+y=18000 ------------------------1
\n" ); document.write( "5.50%x +4.00%y=831
\n" ); document.write( "Multiply by 100
\n" ); document.write( "5.5x+4y=83100.00--------2
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\n" ); document.write( "Multiply (1) by -5.5
\n" ); document.write( "we get
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\n" ); document.write( "-5.5 x -5.5 y= -99000.00
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\n" ); document.write( "Add this to (2)
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\n" ); document.write( "-1.5 y=-15900
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\n" ); document.write( "divide by -1.5
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\n" ); document.write( "y=10600
\n" ); document.write( "$10,600 investment at 4.00%
\n" ); document.write( "Balance $ 7400 investment at 5.50%
\n" ); document.write( "CHECK
\n" ); document.write( "10600 --------- 4.00% ------- 424.00
\n" ); document.write( "7400 ------- 5.50% ------- 407.00
\n" ); document.write( "Total -------------- 831.00
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