An airline charges $150 for an economy class seat, $450 for a business class seat, and $600 for a first class seat. There are three times as many economy class seats
as business class seats on an airplane. The revenue from selling all 60 seats on
the airplane is $15,000. How many of each type of seat does the airplane have?
The airplane has economy class seats,
and first class seats.
business class seats,