The distance between A and B is 720 kilometers. An express train and a slow train travel towards each other from the two places at the same time, and they meet after 4 hours. It is known that the speed of the slow train is that of the express train (4/5), how many kilometers per hour does the express train travel?
甲、乙两地相距720千米，一辆快车与一辆慢车同时从两地相向而行，经过4小时相遇．己知慢车的速度是快车的(4/5)，求快车每小时行多少千米？
<gadget id="calculator">720 / 4</gadget>
<output>180</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">180 * (5/9)</gadget>
<output>100</output>

<result>100</result>