Uncle Wang drove from place A to place B, and traveled 100 kilometers in the first 2 hours. At this speed, it will take a total of 3 hours to go from place A to place B. When returning, Uncle Wang traveled 60 kilometers per hour. How long did it take to return?
王叔叔开车从甲地到乙地，前2小时行了100千米，照这样的速度，从甲地到乙地一共要用3小时．返回时，王叔叔每小时行60千米，返回时用了多长时间？
<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<gadget id="calculator">3 / 60</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">50 * (1/20)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>