Selected Answer
Jatden
Firstly it's better not to type $ in number cell- just type the number but set the format to Currency (and adjust decimal places if needed).
In the revision to your file (attached) , I've done that and set (blue) cell F2 as a threshold value (so you could make it 0, 500, 550 or whatever). The formula for the average of salaries per worker but only above that threshold if (e.g. in F3) is:
=IFERROR(SUMIF(B3:D3,">"&$F$2)/COUNTIF(B3:D3,">"&$F$2),"-")
where the part:
SUMIF(B3:D3,">"&$F$2)
adds cells b3 to D3 but only if they meet the criteria (in bold) which means "greater than the value in fixed cell F2. You could change that for ">500" if you don't want the flexibitity F2 gives.
COUNTIF is identical but counts the cells meeting the criteria. The average is the sum over the count as you will know.
If there are no matching values (so the COUNTIF is 0), you'll get a #DIV0 error so I've wrapped the formula with the IFERROR function, in which case the cell becomes the "-" (or whatever you choose) at the end of the formula.
Hope this makes sense / fixes your problem.