document.write( "Question 521852: A retired couple invested part of $11,400 at 6% interest and the rest at 7.5%. If their annual income from these investments is $783. Find the invested part at each rate? \n" ); document.write( "

Algebra.Com's Answer #346600 by stanbon(75887) $\"\"$ $\"About$

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A retired couple invested part of $11,400 at 6% interest and the rest at 7.5%. If their annual income from these investments is $783. Find the invested part at each rate?
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\n" ); document.write( "Equations:
\n" ); document.write( "x + y = 11,400
\n" ); document.write( "0.075x + 0.06y = 783
\n" ); document.write( "-----------------------------
\n" ); document.write( "Multiply thru 1st equation by 75
\n" ); document.write( "Multiply thru 2nd equation by 1000
\n" ); document.write( "-----
\n" ); document.write( "75x + 75y = 75*11400
\n" ); document.write( "75x + 60y = 783000
\n" ); document.write( "-----
\n" ); document.write( "Subtract and solve for \"y\":
\n" ); document.write( "15y = 72000
\n" ); document.write( "-----
\n" ); document.write( "y = $4800 (amt invested at 6%)
\n" ); document.write( "----------------
\n" ); document.write( "Solve for \"x\":
\n" ); document.write( "x + y = 11,400
\n" ); document.write( "x + 4800 = 11,400
\n" ); document.write( "x = $6600 (amt invest at 7.5%)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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