A farmer can plant up to 28 acres of land with wheat and barley. He can earn $2,000 for every acre he plants with wheat and $3,000 for every acre he plants with barley. His use of a necessary pesticide is limited by federal regulations to 100 gallons for his entire 28 acres. Wheat requires 1.5 gallons of pesticide for every acre planted and barley requires just 2.5 gallon per acre. What is the maximum profit he can make