Answer: $15,000
Explanation:
Let x be the amount invested in the highest-yielding account. Then, Cyndee invested 2x in the lowest-yielding account and 50000 - 3x in the account yielding 5.5%.
The annual interest earned on each account is:
- 0.06(50000 - 3x) for the account yielding 6%
- 0.055(50000 - 3x) for the account yielding 5.5%
- 0.04x for the account yielding the highest interest rate.
The sum of these interests should equal $2400:
0.06(50000 - 3x) + 0.055(50000 - 3x) + 0.04x = 2400
Simplifying this equation, we get:
0.03x = 450
x = 15000
Therefore, Cyndee should invest $15,000 in the account yielding the highest interest rate, $30,000 in the account yielding 4% interest rate, and $5,000 in the account yielding 5.5% interest rate.