Luther, a caterer, is investing some money in equipment and employees to help grow his business. Recently he spent $100 on equipment and hired a server who makes $10 per hour. Luther is hoping to make up these expense at the next job that is scheduled, which pays a base of $50 in addition to $15 per hour that the server works. In theory, this event could pay enough to cancel out Luther's expenditures. How long would the job have to be?