A job can be completed in 24 days by the cooperation of the master and the apprentice. Because the master asked for leave for something, he was away for 10 days in the middle, but it actually took 30 days to complete it. How many days does it take for the master to complete this job alone?
一件工作，师傅和徒弟两人合作24天可以完成，因师傅有事请假，中间离开了10天，实际用了30天完成，师傅单独完成这件工作需要多少天？
<gadget id="calculator">1 / 24</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(1/24) * 30</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(5/4) - 1</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / 10</gadget>
<output>1/40 = around 0.025</output>

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

<result>40</result>