Question 16966
Let x = the amount invested at 10% and ($30,000 - x) the amount invested at 5%
The interest Mrs. Brighton received from these two investments would be:

(10% of $x) + (5% of ($30,000 - $x)) and this = $2,300  So, knowing this we can solve for x, the amount invested at 10%, and once we have that, we can find the amount invested at 5%. Let's set up the appropriate equation after changing the percents to their decimal equivalents: 10% = 0.1 and 5% = 0.05

{{{0.1x + 0.05(30000 - x) = 2300}}} Simplify and solve for x.
{{{0.1x + 1500 - 0.05x = 2300}}} Combine the x-terms.
{{{0.05x + 1500 = 2300}}} Subtract 1500 from both sides.
{{{0.05x = 800}}} Divide both sides by 0.05
{{{x = 16000}}}

$16,000 was invested at 10%
$30,000 - $16,000 = $14,000 was invested at 5%

Check:
0.1($16,000) + 0.05($14,000) = $1,600 + $700 = $2,300 Total interest received.