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?
There was an increase of 100 x 15/100 = 
<gadget id="calculator">100*15/100</gadget>
<output>15</output>
15 visitors in November.
So, the number of visitors in November was 100 + 15 = 
<gadget id="calculator">100+15</gadget>
<output>115</output>
115.
In December, the number of visitors was 115 + 15 = 
<gadget id="calculator">115+15</gadget>
<output>130</output>
130.
Therefore, a total of 100 + 115 + 130 = 
<gadget id="calculator">100+115+130</gadget>
<output>345</output>
345 visitors listed in these three months.

<result>345</result>