Uncle Zhang typed a manuscript and finished typing all (1/5) in 4 hours. According to this calculation, how many hours will it take for Uncle Zhang to finish typing this manuscript.
张叔叔打一篇稿子，4小时打完了全部的(1/5)，照这样计算，张叔叔将这篇稿子全部打完还要用多少小时．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(1/5) / 4</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(4/5) / (1/20)</gadget>
<output>16</output>

<result>16</result>