A project alone takes 40 days, and B alone takes 60 days. Now they are working together, and A rests for a few days due to illness, so it takes 27 days to complete it. How many days does A rest?
一件工程，甲独做要40天，乙独做要60天，现在两人合做，中间甲因病休息了几天，所以27天才完成，甲休息了多少天？
<gadget id="calculator">1 / 60</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">(1/60) * 27</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (9/20)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">1 / 40</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">(11/20) / (1/40)</gadget>
<output>22</output>

<gadget id="calculator">27 - 22</gadget>
<output>5</output>

<result>5</result>