A plant food is made from three chemicals, labeled I, II, and III. In each batch of the plant food, the amounts of chemicals II and III must be in the ratio of 5 to 3. The amount of nitrogen must be at least 29 kg. The percent of nitrogen in the three chemicals is 8%, 4%, and 5%, respectively. If the three chemicals cost $1.03, $0.83, and $0.68 per kilogram, respectively, how much of each should be used to minimize the cost of producing at least 650 kg of the plant food?