There was an increase of 100 x 15/100 = <<100*15/100=15>>15 visitors in November.

So, the number of visitors in November was 100 + 15 = <<100+15=115>>115.

In December, the number of visitors was 115 + 15 = <<115+15=130>>130

Therefore, a total of 100 + 115 + 130 = <<100+115+130=345>>345 visitors listed in these three months.

# Answer

345
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
An online newspaper had listed 100 visitors in October. The number of visitors in November increased by 15%. There were 15 more visitors in December than in November. What is the total number of visitors for these three months?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
345
An online newspaper had listed 100 visitors in October. The number of visitors in November increased by 15%. There were 15 more visitors in December than in November. What is the total number of visitors for these three months?
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