document.write( "Question 1141789: Luis just retired, and has $900,000 to invest. A very safe Certificate of Deposit (CD) account pays 2%, while a riskier bond fund pays 4.5% in interest. Luis figures he needs $36,000 a year in interest to live on. How much should he invest in each account to make enough interest while minimizing his risk?\r
\n" ); document.write( "\n" ); document.write( "How much $ at 2%?\r
\n" ); document.write( "\n" ); document.write( "How much $ at 4.5% \n" ); document.write( "

Algebra.Com's Answer #762429 by ikleyn(52794) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "

\r\n" );
document.write( "Let x dollars be the amount (now unknown) to invest at 4.5%.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Then the amount at 2% is the rest (900000-x) dollars.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "The total interest equation is\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "    0.02*(900000-x) + 0.045*x = 36000.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "From the equation, express x and calculate\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "    x =  = 720000.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "ANSWER.  $720000 must be invested at 4.5% and the rest (900000-720000) = 180000 dollars must be invested at 2%.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "CHECK.  0.045*720000 + 0.02*180000 = 36000 dollars.   ! Correct !\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( "Solved.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "----------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "It is a standard and typical problem on investments.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "If you need more details, or if you want to see other similar problems solved by different methods, look into the lesson \r
\n" ); document.write( "\n" ); document.write( " - Using systems of equations to solve problems on investment\r
\n" ); document.write( "\n" ); document.write( "in this site.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "You will find there different approaches (using one equation or a system of two equations in two unknowns), as well as
\n" ); document.write( "different methods of solution to the equations (Substitution, Elimination).\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( " - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The referred lesson is the part of this online textbook under the topic \"Systems of two linear equations in two unknowns\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );