A ship travels at a speed of 20km per hour. It takes 8 hours to get from point A to point B. Due to the headwind, the speed slows down (1/5) compared to the original speed. How many hours did it take to return? ﹙Using proportional solutions﹚
一艘轮船每小时20km的速度行驶，8小时由甲地到达乙地，回来因是逆风，速度比原来减慢(1/5)，回来时航行了多少小时？﹙用比例解﹚
<gadget id="calculator">20 * 8</gadget>
<output>160</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">20 - 4</gadget>
<output>16</output>

<gadget id="calculator">160 / 16</gadget>
<output>10</output>

<result>10</result>