The distance between A and B is 1800 kilometers. An airplane flies from A to B at a speed of 360 kilometers per hour. When it returns, it takes 1 hour less than when it goes there with a favorable wind. How many kilometers per hour is the average round trip?
甲乙两地相距1800千米，一架飞机从甲地飞往乙地，每小时飞行360千米，返回时顺风，比去时少用1小时．往返平均每小时飞行多少千米？
<gadget id="calculator">1_800 / 360</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">1_800 * (2/9)</gadget>
<output>400</output>

<result>400</result>