To make a Tibetan-style tent for the "Shoton" Festival, it takes 30 days for the master to complete it alone, and half a month for the apprentice to complete it alone. If everyone takes turns working for one day in the order of master, apprentice, master, apprentice, ... how many days will it take to complete the tent.
为"雪顿"节做一顶藏式帐篷，师傅单独完成要用30天，徒弟单独完成，要多用半个月．如果按照师、徒、师、徒、…的顺序每人轮流工作一天，这顶帐篷多少天才能做完．
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">30 + 15</gadget>
<output>45</output>

<gadget id="calculator">1 / 45</gadget>
<output>1/45 = around 0.022222</output>

<gadget id="calculator">(1/30) + (1/45)</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">1 / (1/18)</gadget>
<output>18</output>

<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<result>36</result>