document.write( "Question 723850: Sergio invests part of his 90,000 at 4% and the rest at 3%. How much is invested at each rate if he makes a total income of 3,100 annually?\r
\n" ); document.write( "\n" ); document.write( "--HELP ME PLEASE I CANT DO IT BY MYSELF :( \n" ); document.write( "
Algebra.Com's Answer #443401 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
Part I 3.00% per annum ------------- Amount invested =x
\n" ); document.write( "Part II 4.00% per annum ------------ Amount invested = y =
\n" ); document.write( " 90000
\n" ); document.write( "Interest----- 3100
\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= 90000 -------------1
\n" ); document.write( "Interest on both investments
\n" ); document.write( "3.00% x + 4.00% y= 3100
\n" ); document.write( "Multiply by 100
\n" ); document.write( "3 x + 4 y= 310000.00 --------2
\n" ); document.write( "Multiply (1) by -3
\n" ); document.write( "we get
\n" ); document.write( "-3 x -3 y= -270000.00
\n" ); document.write( "Add this to (2)
\n" ); document.write( "0 x 1 y= 40000
\n" ); document.write( "divide by 1
\n" ); document.write( " y = 40000
\n" ); document.write( "Part I 3.00% $ 50000
\n" ); document.write( "Part II 4.00% $ 40000
\n" ); document.write( "
\n" ); document.write( "CHECK
\n" ); document.write( "50000 --------- 3.00% ------- 1500.00
\n" ); document.write( "40000 ------------- 4.00% ------- 1600.00
\n" ); document.write( "Total -------------------- 3100.00
\n" ); document.write( "
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( " \n" ); document.write( "
\n" );