A truck delivers goods from place A to place B, which is 315km away, and traveled 135km in the first 3 hours. According to this calculation, how many hours does it take for the truck to complete the journey?
一辆货车从甲地送货去相距315km的乙地，前3小时行了135km，照这样计算，这辆货车行完全程需要多少小时？
<gadget id="calculator">135 / 3</gadget>
<output>45</output>

<gadget id="calculator">315 / 45</gadget>
<output>7</output>

<result>7</result>