Answer:
Mr. Robins commision rate is 15%.
Explanation:
Formula

As given
Mr robbins earns a commission on each airfare he books.
At the end of the day,he had booked $208.60 worth if airfare and earned $31.29.
Here
Part value = $31.29
Total value = $208.60
Put in the formula


Percentage = 15%
Therefore the Mr. Robins commision rate is 15%.