certain army is marching in a 300-meter-long team at a speed of 4 meters per second. The correspondent at the end of the team immediately chases the commander who is at the front at a speed of 8 meters per second after receiving the order. Immediately return to the original position at the same speed, how many seconds does it take from receiving the command to returning to the original position?
某军排着300米长的队伍行军，速度是4米/秒，走在队伍最后的通讯员，接到命令后立即以8米/秒的速度追赶走在最前面的指挥员，追到后又立即以相同速度返回原来位置，从接到命令到返回原位共用多少秒？
<gadget id="calculator">8 - 4</gadget>
<output>4</output>

<gadget id="calculator">300 / 4</gadget>
<output>75</output>

<gadget id="calculator">8 + 4</gadget>
<output>12</output>

<gadget id="calculator">300 / 12</gadget>
<output>25</output>

<gadget id="calculator">75 + 25</gadget>
<output>100</output>

<result>100</result>