The gas cost 8*3.5=$<<8*3.5=28>>28

The mileage expenses cost 320*.5=$<<320*.5=160>>160

So in total he paid 150+28+160=$<<150+28+160=338>>338

# Answer

338
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
John rents a car to visit his family.  It cost $150 to rent the car.  He also had to buy 8 gallons of gas to fill it up and gas is $3.50 per gallon.  The final expense is $.50 per mile.  If he drove 320 miles how much did it cost?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
338
John rents a car to visit his family.  It cost $150 to rent the car.  He also had to buy 8 gallons of gas to fill it up and gas is $3.50 per gallon.  The final expense is $.50 per mile.  If he drove 320 miles how much did it cost?
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