document.write( "Question 257358: Part of a $12,000 investment earned interest at a rate of 7%, and the rest earned interest at a rate of 9%. The combined interest earned at the end of 1 year was $890. How much was invested at each rate? \n" ); document.write( "

Algebra.Com's Answer #189288 by drk(1908) $\"\"$ $\"About$

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This is a I=PRT problem. IN this case we have 2 rates,so we get
\n" ); document.write( "(i) $\"I+=+prt+%2B+prt\"$
\n" ); document.write( "From above, (i) becomes
\n" ); document.write( "(ii) $\"890+=+x%28.07%29%281%29+%2B+%2812000-x%29%28.09%29%281%29\"$
\n" ); document.write( "which is
\n" ); document.write( " $\"890+=+.07x+%2B+1080+-.09x\"$
\n" ); document.write( " $\"890+=+-.02x+%2B+1080\"$
\n" ); document.write( " $\".02x+=+190\"$
\n" ); document.write( "x = 9500
\n" ); document.write( "12000-x = 2500
\n" ); document.write( "So it appears we have
\n" ); document.write( "9500 @ 7%
\n" ); document.write( "2500 @ 9% \n" ); document.write( "

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