A car traveled a total of 210 kilometers from 9 am to 4 pm. How many miles per hour on average?
一辆汽车从上午9时到下午4时共行了210千米．平均每小时行驶多少千米？
<gadget id="calculator">12 - 9</gadget>
<output>3</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">210 / 7</gadget>
<output>30</output>

<result>30</result>