To calculate the simple interest earned by Diego, you can use the formula for simple interest:
where:
is the interest, is the principal amount (initial deposit), is the rate of interest (expressed as a decimal), is the time in years.
In this case:
years
Now, we can calculate the interest:
So, the interest earned after four years is $2,400.
To find the total amount Diego will have after closing his account, we add the interest to the principal:
Therefore, Diego will have a total of $12,400 after four years.