Mr. Wang’s house is decorated, and there are 60m**2 walls that need to be pasted with wallpaper. If worker A alone takes 4 hours to finish it, worker B takes 5 hours to finish it alone. If two people cooperate, how many hours can the post be finished?
王老师家装修，有60m**2的墙面需要贴墙纸，如果甲工人单独贴需要4小时完成，乙工人单独贴需5小时完成．如果两人合作，几小时可以贴完？
<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">60 / 5</gadget>
<output>12</output>

<gadget id="calculator">15 + 12</gadget>
<output>27</output>

<gadget id="calculator">60 / 27</gadget>
<output>20/9 = around 2.222222</output>

<result>20/9 = around 2.222222</result>