Answer: You invested $6000 in both accounts.
Step-by-step explanation:
Let x represent the amount invested in the account earning 4.5% interest.
Let y represent the amount invested in the account earning 5% interest.
You invested a total of $12,000 at 4.5 percent and 5 percent simple interest. This means that
x + y = 12000
The formula for simple interest is expressed as
I = PRT/100
Where
P represents the principal
R represents interest rate
T represents time in years
I = interest after t years
Considering the account earning 4.5%
I = (x × 4.5 × 1)/100 = 0.045x
Considering the account earning 5%
I = (y × 5 × 1)/100 = 0.05y
During one year, the two accounts earned $570. . This means that
0.045x + 0.05y = 570 - - - - - - - - - - 1
Substituting x = 12000 - y into equation 1, it becomes
0.045(12000 - y) + 0.05y = 570
540 - 0.045y + 0.05y = 570
- 0.045y + 0.05y = 570 - 540
0.005y = 30
y = 30/0.005 = 6000
x = 12000 - y = 12000 - 6000
x = $6000
