Projects A and B are completed by teams 1 and 2 respectively. On a sunny day, it takes 12 days for the first team to complete project A, and 15 days for the second team to complete project B. In rainy days, the work efficiency of the first team will drop by 40%. The work efficiency of the team will drop by 10%. As a result, the two teams complete the project at the same time. Then, during the construction days, how many days are there rainy days?
甲、乙两项工程分别由一、二队来完成，在晴天，一队完成甲工程需要12天，二队完成乙工程需要15天；在雨天，一队的工作效率要下降40%，二队的工作效率要下降10%，结果两队同时完成这项工程，那么，在施工的日子里，雨天有多少天？
<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/12) - (1/15)</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">3 / 50</gadget>
<output>3/50 = around 0.06</output>

<gadget id="calculator">(3/50) * (1/12)</gadget>
<output>1/200 = around 0.005</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * (1/15)</gadget>
<output>1/300 = around 0.003333</output>

<gadget id="calculator">(1/200) - (1/300)</gadget>
<output>1/600 = around 0.001667</output>

<gadget id="calculator">(1/60) / (1/600)</gadget>
<output>10</output>

<result>10</result>