Uncle Wang drove from A to B for errands. When he went there, he traveled 70 kilometers per hour and took 8 hours. It only took 7 hours to return by the original route. What is the return speed?
王叔叔开车从甲地去乙地办事，去时每小时行70千米，用了8小时．按原路返回时只用了7小时，返回速度是多少？
<gadget id="calculator">8 / 7</gadget>
<output>8/7 = around 1.142857</output>

<gadget id="calculator">70 * (8/7)</gadget>
<output>80</output>

<result>80</result>