Really stuck on this question, could someone lend me a hand?

As a receptionist for a hospital, one of Elizabeth’s tasks is to schedule appointments. She allots 60 minutes for the first visit and 30 minutes for a follow-up. The doctor cannot perform more than seven follow-ups per day. The hospital has eight hours available for appointments. The first visit costs $120 and the follow-up costs $70. Let x be the number of first visit and y be the number of follow-ups.