100*.8=<<100*.8=80>>80 customers bought something

That means they were worth 80*25=$<<80*25=2000>>2000

So he gained 2000-1000=$<<2000-1000=1000>>1000 from the ad

# Answer

1000
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
James pays $1000 for advertising.  It brought 100 customers to his site and 80% of those bought something at the store that cost $25.  How much profit does he gain from the ad?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
1000
James pays $1000 for advertising.  It brought 100 customers to his site and 80% of those bought something at the store that cost $25.  How much profit does he gain from the ad?
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