According to an evening news report: In the first quarter of this year, the ratio of the number of days with good air quality to the number of smog days in Ningbo City was 2:5, of which 16 days had good air quality, so how many days are there smog days?
据某晚报报道：今年第一季度，宁波市空气质量优的天数与雾霾天数的比是2：5，其中空气质量优的16天，那么雾霾天有多少天？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">16 / (2/5)</gadget>
<output>40</output>

<result>40</result>