A car drives from place A to place B, travels 80 kilometers per hour, and arrives in 2.5 hours; when returning, travels an extra 20 kilometers per hour, how many hours can it reach place A? (Solve with ratio)
一辆汽车从甲地开往乙地，每小时行80千米，2.5小时到达；返回时，每小时多行20千米，几小时可以到达甲地？(用比例解)
<gadget id="calculator">80 * 2.5</gadget>
<output>200</output>

<gadget id="calculator">80 + 20</gadget>
<output>100</output>

<gadget id="calculator">200 / 100</gadget>
<output>2</output>

<result>2</result>