Answer: He invested $350 at 4% and $850 at 5.9%
Explanation:
Let x represent the amount which he invested in the account earning 4% interest.
Let y represent the amount which he invested in the account earning 5.9% interest.
Simone invests 1200 into two savings accounts. One account earns 4% annual interest and the other earns 5.9% annual interest. This means that
x + y = 1200
The formula for determining simple interest is expressed as
I = PRT/100
Considering the account earning 4% interest,
P = $x
T = 1 year
R = 4℅
I = (x × 4 × 1)/100 = 0.04x
Considering the account earning 5.9% interest,
P = $y
T = 1 year
R = 5.9℅
I = (y × 5.9 × 1)/100 = 0.059y
At the end of 1 year, Simon earned 64.15 in interest. it means that
0.04x + 0.059y = 64.15 - - - - - - - - -1
Substituting x = 1200 - y into equation 1, it becomes
0.04(1200 - y) + 0.059y = 64.15
48 - 0.04y + 0.059y = 64.15
- 0.04y + 0.059y = 64.15 - 48
0.019y = 16.15
y = 16.15/0.019
y = 850
x = 1200 - y = 1200 - 850
x = 350