Two planes fly opposite each other from the Nansha Islands and Guangzhou, and meet at a distance of 200 kilometers from the midpoint after 2 hours. It is known that the speed of the slow plane is 400 kilometers per hour. Find the speed of the fast plane.
两架飞机分别从南沙群岛和广州相对飞出，2小时后在离中点200千米处相遇，已知慢飞机每小时400千米，求快飞机的速度．
<gadget id="calculator">400 * 2</gadget>
<output>800</output>

<gadget id="calculator">200 * 2</gadget>
<output>400</output>

<gadget id="calculator">800 + 400</gadget>
<output>1_200</output>

<gadget id="calculator">1_200 / 2</gadget>
<output>600</output>

<result>600</result>