The cost of coffee is determined by the type of coffee beans that are mixed together. The cost of a local mix of Arabica and Robusta beans is modeled by the equation below, where A = the pounds of Arabica and R = pounds of Robusta:
700A + 1200R = 1,000,000
If a mixture contains 1000 pounds of Arabica beans, how many pounds of Robusta beans should be in the mixture?
R = ________________ pounds