truck travels from A to B at a speed of 36 km/h, arrives at B in 5 hours, and travels 45 km/h when returning from B. How long does it take for the truck to return?
一辆货车从甲地往返乙地，去时速度是36千米/每小时，5小时到达乙地，从乙地返回时每小时行驶45千米，货车返回时需要多少时间？
<gadget id="calculator">5 / 45</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">36 * (1/9)</gadget>
<output>4</output>

<result>4</result>