The price of the book is down by: 100*0.2 = $<<100*0.2=20>>20.

So the new price of the movie ticket is: 100 - 20 = $<<100-20=80>>80.

# Answer

80
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Last week, the price of a movie ticket was $100. This year the price is down by 20%. What's the new price of the movie ticket?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
80
Last week, the price of a movie ticket was $100. This year the price is down by 20%. What's the new price of the movie ticket?
train