Question: 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? Think carefully first, then make a decision:
The region of plain A has a total of 200 - 50 = 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 = 350 square miles. So the answer is 350.