The parking lot is 400*500=<<400*500=200000>>200,000

There are 200,000*.8=<<200000*.8=160000>>160,000 square feet of parking space

That means he can park 16,0000/10=16000 cars

# Answer

16000
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
James paves a new parking lot.  It is 400 feet by 500 feet.  Only 80% of that is useable for parking.  It takes 10 square feet to park a car.  How many cars can be parked?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
16000
James paves a new parking lot.  It is 400 feet by 500 feet.  Only 80% of that is useable for parking.  It takes 10 square feet to park a car.  How many cars can be parked?
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