Two trucks delivered fertilizers to the farm. The first truck drove from the county town to the farm at a speed of 30 kilometers per hour. The second truck drove 2 hours late, but the two trucks arrived at the same time. Given that the distance from the county seat to the farm is 180 kilometers, how many kilometers does the second car travel per hour?
两辆卡车为农场送化肥，第一辆车以每小时30千米的速度由县城开往农场，第二辆车晚开了2小时，结果两车同时到达．已知县城到农场的距离是180千米，第二辆车每小时行多少千米．
<gadget id="calculator">180 / 30</gadget>
<output>6</output>

<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<gadget id="calculator">180 / 4</gadget>
<output>45</output>

<result>45</result>