The distance between AB and AB is 960 kilometers. A passenger train and a freight train depart from the two places at the same time and meet each other after 4 hours. It is known that the speed of the passenger car is three times the speed of the train, how many kilometers per hour does the passenger car travel more than the freight car per hour?
AB两地相距960千米，一列客车和一列货车同时从两地相对开出，经过4小时后相遇．已知客车速度是火车速度的3倍，求客车每小时比货车每小时多走多少千米？
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">960 / 4 / 4</gadget>
<output>60</output>

<gadget id="calculator">60 * 3</gadget>
<output>180</output>

<gadget id="calculator">180 - 60</gadget>
<output>120</output>

<result>120</result>