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.