Sally's balance after one year can be found using the simple interest formula:
Interest=Principal×Rate×Time\text{Interest}=\text{Principal}\times \text{Rate}\times \text{Time}Interest=Principal×Rate×Time
Here:
- Principal = $4,000
- Rate = 2.1% = 0.021
- Time = 1 year
Calculate the interest:
Interest=4000×0.021×1=84\text{Interest}=4000\times 0.021\times 1=84Interest=4000×0.021×1=84
Add interest to the principal to find the balance:
Balance=4000+84=4084\text{Balance}=4000+84=4084Balance=4000+84=4084
Sally's balance after one year is $4,084.
