A car drives from place A to place B and travels 40 kilometers per hour. It has been driven for 4.5 hours. The ratio of the distance traveled to the distance not traveled is 3:7. How many hours will it take for the remaining distance?
一辆汽车从甲地开到乙地，每小时行40千米，已经行了4.5小时，已行的路程与未行的路程比是3：7，剩下的路程还需要几小时？
<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">4.5 / (3/10)</gadget>
<output>15</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">(7/10) / 40</gadget>
<output>7/400 = around 0.0175</output>

<gadget id="calculator">40 * 15 * (7/400)</gadget>
<output>21/2 = around 10.5</output>

<result>21/2 = around 10.5</result>