The fuel carried by a combat aircraft can be used for up to 8 hours. The plane travels 650 kilometers per hour when it goes out, and flies 975 kilometers per hour when it returns. How many kilometers does this plane fly at most before it needs to return?
一架战斗飞机所带的燃料最多可以用8小时．飞机去时每小时行650千米，返回时每小时飞行975千米，这架飞机最多飞出多少千米就需返回？
<gadget id="calculator">1 / 650</gadget>
<output>1/650 = around 0.001538</output>

<gadget id="calculator">1 / 975</gadget>
<output>1/975 = around 0.001026</output>

<gadget id="calculator">(1/650) + (1/975)</gadget>
<output>1/390 = around 0.002564</output>

<gadget id="calculator">8 / (1/390)</gadget>
<output>3_120</output>

<result>3_120</result>