Jay and his friends have set up a baseball tournament. He can rent a baseball field for a daily charge of $200 and equipment for $150 per day. If he hires independent umpires, he would need to pay $280 for the day. He would arrange to have caps made for each player at a cost of $4 each. If John can get 90 people to participate, what would he have to charge each of them to recover his costs?