Obviously, the family went at a speed of 45 km/h, and it took 8 hours to arrive. When they came back, there were many vehicles and the speed was 36 km/h. How many hours did it take them to come back?
明明一家去时速度是45千米/时，行了8小时到达．回来时由于车辆较多，速度是36千米/时，他们回来用了多少小时？
<gadget id="calculator">8 / 36</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">45 * (2/9)</gadget>
<output>10</output>

<result>10</result>