The region of plain A has a total of 200 - 50 = <<200-50=150>>150 square miles.

The total number of square miles for both plains is 150 square miles for plain A + 200 square miles for plain B = <<150+200=350>>350 square miles

# Answer

350
<|im_start|>system
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<|im_start|>user
The region east of plain A is 50 square miles less than the region east of plain B. If plain B has 200 square miles, how many square miles do the plains have in total?
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<|im_start|>assistant

user
350
The region east of plain A is 50 square miles less than the region east of plain B. If plain B has 200 square miles, how many square miles do the plains have in total?
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