question: Uncle Ben has four horses. Each horse can consume five pounds of oats per meal. He feeds his horses twice a day. If one bag contains 50-pounds of oats,  how many bags of oats does he need to fed his horses for five days?
answer: The four horses can consume 4 x 5 pounds = <<4*5=20>>20 pounds of oats per meal.
  Thus, they can consume 2 x 20 pounds = <<2*20=40>>40 pounds of oats a day.
  So, uncle Ben needs 5 x 40 pounds = <<5*40=200>>200 pounds of oats to fed his horses for five days.
  Therefore, uncle Ben needs 200/50 = <<200/50=4>>4 bags of oats.
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