Explanation:
Let's assume the amount Mackey initially invested in the 6% account is x dollars.
According to the given information, Mackey invested $1000 more than x in the 8.5% account, which means she invested (x + $1000) dollars in that account.
The total interest earned from the 6% account would be 0.06x dollars, and the total interest earned from the 8.5% account would be 0.085(x + $1000) dollars.
The total interest earned in the year is given as $737.50, so we can set up the equation:
0.06x + 0.085(x + $1000) = $737.50
Simplifying the equation:
0.06x + 0.085x + 0.085($1000) = $737.50
Combining like terms:
0.145x + $85 = $737.50
Subtracting $85 from both sides:
0.145x = $737.50 - $85
0.145x = $652.50
Dividing both sides by 0.145:
x = $652.50 / 0.145
x ≈ $4500
Therefore, Mackey initially invested approximately $4500 in the 6% account, and she invested $1000 more, which means she invested a total of $5500.