Answer: Amount invested at 6% equals $28400
Amount invested at 10% equals $14200
Explanation:
Let x represent the amount invested at 6%.
Let y represent the amount invested at 10%.
He puts twice as much in the lower-yielding account because it is less risky. This means that x = 2y
The formula for determining simple interest is expressed as
I = PRT/100
Where
I represents interest on the investment.
P represents the principal or amount invested
R represents interest rate
T represents the duration of the investment in years.
Considering the amount invested at 6%,
P = x
R = 6 %
T = 1 year
I = (x × 6 × 1)/100 = $0.06x
Considering the amount invested at 6%,
P = y
R = 10 %
T = 1 year
I = (y × 10 × 1)/100 = $0.1y
His annual interest is $3124. This means that
0.06x + 0.1y = 3124 - - - - - - - - - -1
Substituting x = 2y into equation 1, it becomes
0.06 × 2y + 0.1y = 3124
0.12y + 0.1y = 3124
0.22y = 3124
y = 3124/0.22
y = $14200
x = 2y = 2 × 14200
x = $28400