Master Wang produced 800 parts, and completed 25% of the total in the first 4 hours. According to this calculation, how many hours will it take to complete the remaining parts? (Choose the easiest 3 solutions, one of which is a proportional solution)
王师傅生产800个零件，前4小时完成了总数的25%，照这样计算，余下的零件还要几小时完成？(选择最简捷的3种解法，其中一种比例解)
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(1/4) / 4</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">1 * (1/16)</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">(3/4) / (1/16)</gadget>
<output>12</output>

<result>12</result>