The distance from Nanjing to Shanghai is 280 kilometers. A car will be 40 kilometers away from Shanghai after 3 hours from Nanjing. How many hours will it take for the car to arrive in Shanghai?
南京到上海有280千米，一辆汽车从南京出发3小时后离上海还有40千米，照这样这辆汽车再开几小时到达上海？
<gadget id="calculator">280 - 40</gadget>
<output>240</output>

<gadget id="calculator">240 / 3</gadget>
<output>80</output>

<gadget id="calculator">40 / 80</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>