Two engineering teams, A and B, are in charge of two projects respectively. On a sunny day, it takes A 10 days to complete the project, and B 16 days to complete the project. On a rainy day, the work efficiency of A and B is 30% and 80% of that in sunny days, respectively. The actual situation is that the two teams start and finish work at the same time. How many days will it rain during the construction period?
甲、乙两个工程队分别负责两项工程．晴天，甲完成工程需10天，乙完成工程需16天，雨天，甲和乙的工作效率分别是晴天时的30%和80%．实际情况是两队同时开工、完工．在施工期间下雨的天数是多少．
<gadget id="calculator">16 + 9</gadget>
<output>25</output>

<gadget id="calculator">16 / 25</gadget>
<output>16/25 = around 0.64</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(16/25) / (1/10)</gadget>
<output>32/5 = around 6.4</output>

<gadget id="calculator">1 / 16</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/16) * (4/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(1/10) * (3/10)</gadget>
<output>3/100 = around 0.03</output>

<gadget id="calculator">(1/20) - (3/100)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/10) - (1/16)</gadget>
<output>3/80 = around 0.0375</output>

<gadget id="calculator">(1/50) / (3/80)</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">1 / (8/15)</gadget>
<output>15/8 = around 1.875</output>

<gadget id="calculator">(32/5) * (15/8)</gadget>
<output>12</output>

<result>12</result>