Final answer:
Tamara will earn $1,800 in interest on her $15,000 investment at the end of three years.
Step-by-step explanation:
Using the simple interest formula, we can calculate the interest Tamara will earn on her investment. The formula is: A = P * R * T, where A is the total amount, P is the principal amount, R is the interest rate, and T is the time period.
Plugging in the values: P = $15,000, R = 4% (or 0.04 as a decimal), and T = 3 years, we can calculate the interest as follows:
A = $15,000 * 0.04 * 3 = $1,800
Therefore, Tamara will earn $1,800 in interest on her investment at the end of three years.