A total of 630 kilometers from point A to point B, a car from point A to point B took 9 o'clock, and every time it returned, it traveled 20 kilometers longer than when it went there. How long does it take to go back and forth?
甲地到乙地共630千米，一辆汽车从甲地到乙地用了9时，返回时每时比去时多行20千米，往返共用多长时间？
<gadget id="calculator">630 / 9</gadget>
<output>70</output>

<gadget id="calculator">70 + 20</gadget>
<output>90</output>

<gadget id="calculator">630 / 90</gadget>
<output>7</output>

<gadget id="calculator">7 + 9</gadget>
<output>16</output>

<result>16</result>