passenger car drives from place A to place B. It travels the whole distance (1/5) on the first day and 450 kilometers on the second day. At this time, the ratio of the distance traveled to the remaining distance is 3:7 ． How many kilometers are there between A and B?
一辆客车从甲地开往乙地，第一天行了全程的(1/5)，第二天行了450千米，这时已行的路程与剩下的路程的比是3：7．甲乙两地相距多少千米？
<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(3/10) - (1/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">450 / (1/10)</gadget>
<output>4_500</output>

<result>4_500</result>