The fuel on a plane can be used for up to 9 hours. When the plane goes with the wind, it can fly 1500 kilometers per hour. When it flies back against the wind, it can fly 1200 kilometers per hour. How many kilometers can the plane fly at most? Need to fly back?
一架飞机所带油料最多可以用9小时，飞机去时顺风，每小时可以飞1500千米，飞回时逆风，每小时可以飞1200千米，问这架飞机最多可以飞出多少千米就需要往回飞？
<gadget id="calculator">1_500 * 4</gadget>
<output>6_000</output>

<result>6_000</result>