The highway from Nanjing to Xinghua is about 310 kilometers long. Two cars drove opposite each other at the same time and met after 2 hours. A car from Xinghua travels 80 kilometers per hour, how many kilometers per hour does a train from Nanjing travel?
从南京到兴化的公路长约310千米，两辆汽车从两地同时相对开出，经过2小时相遇．从兴化开出的汽车每小时行驶80千米，从南京开出的火车每小时行驶多少千米？
<gadget id="calculator">2 * 80</gadget>
<output>160</output>

<gadget id="calculator">310 - 160</gadget>
<output>150</output>

<gadget id="calculator">150 / 2</gadget>
<output>75</output>

<result>75</result>