document.write( "Question 889589: Mariel invested $1oo,ooo in two business accounts earning 8% and 7 1/2% interest. If both investments earn a total of $7,700, how much was invested at each rate ? \n" ); document.write( "
Algebra.Com's Answer #538258 by mananth(16946)\"\" \"About 
You can put this solution on YOUR website!
Part I 8.00% per annum ------------- Amount invested =x
\n" ); document.write( "Part II 7.50% per annum ------------ Amount invested = y
\n" ); document.write( " 100000
\n" ); document.write( "Interest----- 7700.00
\n" ); document.write( "
\n" ); document.write( "Part I 8.00% per annum ---x
\n" ); document.write( "Part II 7.50% per annum ---y
\n" ); document.write( "Total investment
\n" ); document.write( "x + 1 y= 100000 -------------1
\n" ); document.write( "Interest on both investments
\n" ); document.write( "8.00% x + 7.50% y= 7700
\n" ); document.write( "Multiply by 100
\n" ); document.write( "8 x + 7.5 y= 770000.00 --------2
\n" ); document.write( "Multiply (1) by -8
\n" ); document.write( "we get
\n" ); document.write( "-8 x -8 y= -800000.00
\n" ); document.write( "Add this to (2)
\n" ); document.write( "0 x -0.5 y= -30000
\n" ); document.write( "divide by -0.5
\n" ); document.write( " y = 60000
\n" ); document.write( "Part I 8.00% $ 40000
\n" ); document.write( "Part II 7.50% $ 60000
\n" ); document.write( "
\n" ); document.write( "CHECK
\n" ); document.write( "40000 --------- 8.00% ------- 3200.00
\n" ); document.write( "60000 ------------- 7.50% ------- 4500.00
\n" ); document.write( "Total -------------------- 7700.00
\n" ); document.write( "
\n" ); document.write( "m.ananth@hotmail.ca
\n" ); document.write( " \n" ); document.write( "
\n" );