document.write( "Question 882353: carter fenton earned $12,000 last year by giving tennis lessons. He invested part of the money at 3% simple interest and the rest at 4%. In one year, he earned a total of $440 in interest. How much did hr invest at each rate? \n" ); document.write( "
Algebra.Com's Answer #532802 by mananth(16946)\"\" \"About 
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Part I 3.00% per annum ------------- Amount invested =x
\n" ); document.write( "Part II 4.00% per annum ------------ Amount invested = y
\n" ); document.write( " 12000
\n" ); document.write( "Interest----- 440.00
\n" ); document.write( "
\n" ); document.write( "Part I 3.00% per annum ---x
\n" ); document.write( "Part II 4.00% per annum ---y
\n" ); document.write( "Total investment
\n" ); document.write( "x + 1 y= 12000 -------------1
\n" ); document.write( "Interest on both investments
\n" ); document.write( "3.00% x + 4.00% y= 440
\n" ); document.write( "Multiply by 100
\n" ); document.write( "3 x + 4 y= 44000.00 --------2
\n" ); document.write( "Multiply (1) by -3
\n" ); document.write( "we get
\n" ); document.write( "-3 x -3 y= -36000.00
\n" ); document.write( "Add this to (2)
\n" ); document.write( "0 x 1 y= 8000
\n" ); document.write( "divide by 1
\n" ); document.write( " y = 8000
\n" ); document.write( "Part I 3.00% $ 4000
\n" ); document.write( "Part II 4.00% $ 8000
\n" ); document.write( "
\n" ); document.write( "CHECK
\n" ); document.write( "4000 --------- 3.00% ------- 120.00
\n" ); document.write( "8000 ------------- 4.00% ------- 320.00
\n" ); document.write( "Total -------------------- 440.00
\n" ); document.write( "
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( " \n" ); document.write( "
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