He wants to write 3*400=<<3*400=1200>>1200 pages

So it will take him 1200/20=<<1200/20=60>>60 days

# Answer

60
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
John writes 20 pages a day.  How long will it take him to write 3 books that are 400 pages each?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
60
John writes 20 pages a day.  How long will it take him to write 3 books that are 400 pages each?
train