Final answer:
The simple interest rate earned on a $2100 certificate of deposit held for 66 days, which increased in value to $2108.47, is approximately 1.7%. This is calculated using the formula for simple interest and converting the holding period to a fraction of a year.
Step-by-step explanation:
Calculating Simple Interest Rate
To find out the simple interest rate that was earned on a certificate of deposit (CD), you can use the formula for simple interest:
Simple Interest = Principal × Rate × Time
In the given problem, a $2100 CD held for 66 days increased in value to $2108.47. The interest earned can be calculated as follows:
Interest Earned = Final Amount - Principal = $2108.47 - $2100 = $8.47
To find the annual interest rate, we convert 66 days into a fraction of the year (assuming 360 days in a year):
Time (in years) = 66 / 360
Now we can plug the values into the simple interest formula to solve for the rate:
$8.47 = $2100 × Rate × (66/360)
Rate = ($8.47 / ($2100 × (66/360)))
After performing the calculation, we find that the Rate is approximately 0.017 or 1.7%.
So, the simple interest rate earned on the CD for 66 days was 1.7%.