It's a simple word problem but I'm a bit unsure on how to write the equations out. I'm alright after I've written it out.

An airlines company offers group discounts. The price for a flight is $150 per person for the first 15 passengers of the group. For larger groups, each passenger of the group receives a $1.2 discoutn for every passenger in excess of the first 15 passengers. The group maximum size is limited to 70 passengers.

1) Determine the revenue R of the company as a function of the number of passengers Q of the group.

2) For which quantities Q would the revenue R be 0?