Brett is comparing the cost of a fresh lobster dinner at two different restaurants. The first restaurant charges $30 for the meal, plus $1 per kilogram for the lobster he picks. At the second restaurant, Brett would pay $2 per kilogram for the lobster, in addition to $15 for the meal. Brett realizes that, in theory, dinner at both restaurants could cost the same amount if the lobster had a certain weight. How much would Brett pay for his dinner?