Question 179560
Let x = the amount Walt invested at 7%, so the remainder ($12000-x) was invested at 9%.
The interest earned on these two amounts can be expressed as:
(7%)(x) + (9%)($12000-x) and the sum of these two amounts is given as $970.00
Now you can write the equation that will allow you to so;ve for x, the amount invested at 7%.
First, change the percentages to their decimal equivalents:
(7% = 0.07) and (9% = 0.09)
{{{0.07x+0.09(12000-x) = 970}}} Simplifying this, you'll get:
{{{0.07x+1080-0.09x= 970}}} Combine the x-terms.
{{{-0.02x+1080 = 970}}} Subtract 1080 from both sides of the equation.
{{{-0.02x = -110}}} Finally, divide both sides by -0.02
{{{highlight(x = 5500)}}}
$5,500.00 was invested at 7% while $12000-$5500 = $6,500.00 was invested at 9%