To find the gross pay earned by the employee, we need to first calculate the number of acceptable pieces that the employee produced.
The total number of pieces produced by the employee is 483, but 9 of those pieces did not pass inspection. Therefore, the number of acceptable pieces produced by the employee is:
483 - 9 = 474
Now we can calculate the gross pay earned by the employee by multiplying the number of acceptable pieces produced by the piece rate of $1.28:
Gross pay = 474 x $1.28
Gross pay = $606.72
Therefore, the employee earned a gross pay of $606.72.