Question

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?

Answer 1

700a+1200r=1000000       (then plug in the a)
700(1000) +1200r=1000000        (simplify)
700000+1200r=1000000        (subtract 700000 from both sides)
1200r=300000             (divide by 1200 on both sides)
r=250
250 pounds