Amount of commission received by Steve for the first 4 sales of the month = $500
Amount of commission received by Steve for the next 6 sales of the month = $600
Amount of commission made by Steve
for the first 10 sales of the month = (500 + 600) dollars
= 1100 dollars
Average commission received by Steve per sale during the month = 1100/10 dollars
= 110 dollars
So the average commission received by Steve for a single sale during the month is $110. I hope the procedure is clear enough for you to understand.