When a truck travels 30% of the journey from city A to city B, it is still 280 kilometers away from the destination. How many kilometers is the distance from city A to city B?
一辆货车从甲城到乙城，行了全程的30%时，离终点还有280千米，从甲城到乙城相距多少千米？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">280 / (7/10)</gadget>
<output>400</output>

<result>400</result>