document.write( "Question 863519: A woman invested $15,000, part at 7% simple annual interest and part at 8% annual interest. If she receives $1,140 interest per year, how much did she invest at 7%? \n" ); document.write( "
Algebra.Com's Answer #520473 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
Part I 7.00% per annum ------------- Amount invested =x
\n" ); document.write( "Part II 8.00% per annum ------------ Amount invested = y
\n" ); document.write( " 15000
\n" ); document.write( "Interest----- 1140.00
\n" ); document.write( "
\n" ); document.write( "Part I 7.00% per annum ---x
\n" ); document.write( "Part II 8.00% per annum ---y
\n" ); document.write( "Total investment
\n" ); document.write( "x + 1 y= 15000 -------------1
\n" ); document.write( "Interest on both investments
\n" ); document.write( "7.00% x + 8.00% y= 1140
\n" ); document.write( "Multiply by 100
\n" ); document.write( "7 x + 8 y= 114000.00 --------2
\n" ); document.write( "Multiply (1) by -7
\n" ); document.write( "we get
\n" ); document.write( "-7 x -7 y= -105000.00
\n" ); document.write( "Add this to (2)
\n" ); document.write( "0 x 1 y= 9000
\n" ); document.write( "divide by 1
\n" ); document.write( " y = 9000
\n" ); document.write( "Part I 7.00% $ 6000
\n" ); document.write( "Part II 8.00% $ 9000
\n" ); document.write( "
\n" ); document.write( "CHECK
\n" ); document.write( "6000 --------- 7.00% ------- 420.00
\n" ); document.write( "9000 ------------- 8.00% ------- 720.00
\n" ); document.write( "Total -------------------- 1140.00
\n" ); document.write( "
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( " \n" ); document.write( "
\n" );