Inverse and Direct Variation Word Problems - Examples

For the summer, Ben and a bunch of his friends want to rent a beach house for a week. Ben decides to invite $9$ friends; they (including Ben) agree to split the cost equally and everyone pays 250 dollars. Is the relation between the number of people going and cost for each person directly or inversely proportional? How much will it cost for each friend if Ben only invites $4$ friends?