group of students set off from the school for military training, traveling at a speed of 5km/h. After walking for 4.5km, a correspondent returned to the school by bicycle to report the message, and then he immediately chased the group. The speed of the correspondent was 14km/h. After catching up with the team at a distance of 5km from the army, ask: What is the distance from the school to the army? (Reporting time is ignored)
一队学生从学校出发去部队军训，行进速度是5km/h，走了4.5km后，一名通讯员骑车按原路返回学校报信，然后他随即追赶队伍，通讯员的速度是14km/h，他在距部队5km处追上队伍，问：学校到部队的距离是多少？(报信时间忽略不计)
<gadget id="calculator">4.5 + 4.5</gadget>
<output>9</output>

<gadget id="calculator">14 - 5</gadget>
<output>9</output>

<gadget id="calculator">9 / 9</gadget>
<output>1</output>

<gadget id="calculator">5 * 1</gadget>
<output>5</output>

<gadget id="calculator">4.5 + 5 + 5</gadget>
<output>14.5</output>

<result>14.5</result>