Final answer:
Dora will earn $21.83 in simple interest to the nearest penny on her saving account after 4 years, based on a principal of $79 and an annual interest rate of 6.9%.
Step-by-step explanation:
The question asks us to calculate the simple interest that Dora will earn on her savings account over a period of 4 years. The savings account has an initial balance of $79 and earns simple interest at an annual rate of 6.9%. To find the total interest earned, we use the formula for simple interest, which is Interest = Principal × Rate × Time. Here, the principal is the initial amount in the savings account, the rate is the annual interest rate, and the time is the number of years the money is invested.
Using Dora's account balance and the given interest rate, the calculation is as follows:
- Principal (P) = $79
- Annual Interest Rate (R) = 6.9% or 0.069 (as a decimal)
- Time (T) in years = 4
Therefore, the simple interest Dora will earn is calculated as:
Interest = $79 × 0.069 × 4 = $21.826
To the nearest penny, the interest would be $21.83.