Answer:
$1000 at a 6.5% rate
$800 at a 5% rate
Explanation:
Let X be the amount invested at a 6.5% rate and Y be the amount invested at a 5% rate.
[tex]X+Y = \$1800\\0.065X+0.05Y=\$105[/tex]
Solving the linear system:
[tex]X+Y -20*(0.065X+0.05Y)= \$1800-(20*\$105)\\-0.3X=-\$300\\X=\$1000\\Y= \$1800-\$1000\\Y=\$800[/tex]
$1000 were invested at a 6.5% rate and $800 at a 5% rate.