Answer:
Commission is money paid to a person or a company for making a sale. It is usually a percent of the sale amount.
As per the given information,
Total monthly sales last month a salesman had $15,200.
Commission he made from those sales is $912.
To find the percent of salesman's commission:
Percentage of salesman commission =

=


On Simplify we get,
Percentage of salesman's commission of his total monthly sales is, 6%