truck and a passenger car travel towards each other from City S and City X respectively at 11:00 am and meet at 3:00 pm. If the distance between the two cities is 640 kilometers, the speed of the truck is that of the passenger car (7/9). How many kilometers per hour does the truck travel on average?
一辆货车和一辆客车上午11时分别从S城和X城同时相向而行，下午3时相遇．如果两城相距640千米，货车的速度是客车的(7/9)．货车平均每小时行多少千米？
<gadget id="calculator">640 / 4</gadget>
<output>160</output>

<gadget id="calculator">9 + 7</gadget>
<output>16</output>

<gadget id="calculator">7 / 16</gadget>
<output>7/16 = around 0.4375</output>

<gadget id="calculator">160 * (7/16)</gadget>
<output>70</output>

<result>70</result>