country a had a population of 1,000, of whom 600 worked an average of 8 hours a day and had a productivity of 2.5. country b had a population of 800, of whom 560 worked 8 hours a day and had productivity of 3.0.

  b.

there are isolated pockets of farming, generally around rivers and oases, which are used for irrigation.

where is the rest of the question. this isn't making sense. can you upload a picture of the question?

answer; knowledge,reason,and judgement;