A truck drives from City A to City B with an average speed of 70 km/h and arrives in 6 hours. Now the truck returns the same way, and it takes 1 hour less to return than when it went. What is the speed of the truck?
一辆货车从甲城开往乙城，行驶的平均速度是70千米/时，6小时到达．现在货车原路返回，返回时比去时少用了1小时，货车返回的速度是多少？
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">6 / 5</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">70 * (6/5)</gadget>
<output>84</output>

<result>84</result>