document.write( "Question 768059: A person invested $7800 for one year,part at 6%, part at 9%, and the remainder at 12%.The total annual income from these investments was $795.The amount of money invested a t 12% was $1200 more than the amounts invested at 6% and 9% combined.What was the amount invested at each rate? \n" ); document.write( "
Algebra.Com's Answer #468050 by mananth(16946)![]() ![]() You can put this solution on YOUR website! A person invested $7800 for one year,part at 6%, part at 9%, and the remainder at 12%.The total annual income from these investments was $795.The amount of money invested a t 12% was $1200 more than the amounts invested at 6% and 9% combined.What was the amount invested at each rate?\r \n" ); document.write( "\n" ); document.write( "6%--------------------x \n" ); document.write( "9%--------------------y\r \n" ); document.write( "\n" ); document.write( "12%-------------------7800-(x+y)\r \n" ); document.write( "\n" ); document.write( "TOTAL INCOME \n" ); document.write( "6%x+9%y+12%*7800-(x+y) = 795\r \n" ); document.write( "\n" ); document.write( "SECOND CONDITION\r \n" ); document.write( "\n" ); document.write( "7800-(x+y)=x+y+1200\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "6%x+9%y+12%*7800-(x+y) = 795 \n" ); document.write( "multiply equation by 100 \n" ); document.write( "6x+9y+12*(7800-(x+y)) =79500\r \n" ); document.write( "\n" ); document.write( "6x+9y+93600-12x-12y=79500 \n" ); document.write( "-6x-3y=79500-93600 \n" ); document.write( "-6x-3y=-14100 \n" ); document.write( "/-3 \n" ); document.write( "2x+y=4700........................(1)\r \n" ); document.write( "\n" ); document.write( "7800-(x+y)x+y+1200 \n" ); document.write( "7800-x-y=x+y+1200 \n" ); document.write( "2x+2y=6600 \n" ); document.write( "/2 \n" ); document.write( "x+y=3300...........................(2)\r \n" ); document.write( "\n" ); document.write( "solve eqn (1) & (2)\r \n" ); document.write( "\n" ); document.write( "2 x + 1 y = 4700 .............1 \n" ); document.write( "Total value \n" ); document.write( "1 x + 1 y = 3300 .............2 \n" ); document.write( "Eliminate y \n" ); document.write( "multiply (1)by -1 \n" ); document.write( "Multiply (2) by 1 \n" ); document.write( "-2 x -1 y = -4700 \n" ); document.write( "1 x + 1 y = 3300 \n" ); document.write( "Add the two equations \n" ); document.write( "-1 x = -1400 \n" ); document.write( "/ -1 \n" ); document.write( "x = 1400 \n" ); document.write( "plug value of x in (1) \n" ); document.write( "2 x + 1 y = 4700 \n" ); document.write( "2800 + y = 4700 \n" ); document.write( " y = 4700 -2800 \n" ); document.write( " y = 1900 \n" ); document.write( " y = 1900 \n" ); document.write( "x= 1400investment at6% \n" ); document.write( "y= 1900 investment at 9% \n" ); document.write( "Balance at 12% \n" ); document.write( "m.ananth@hotmail.ca \n" ); document.write( " \n" ); document.write( " |