Xiaoqiang forgot to bring his notebook when he went to school. When his father found out, he drove to chase after him, and returned home immediately after handing the notebook to him. After Xiaoqiang received the notebook, he walked for another 5 minutes to reach the school, and his father happened to be home at this time. If Dad's speed is three times that of Xiaoqiang's, how much time does it take Xiaoqiang to go from home to school?
小强上学忘了带笔记本，爸爸发现后立即汽车去追，把笔记本交给他后立即返回家．小强接到笔记本后又走了5分钟到达学校，这时爸爸也正好到家．如果爸爸的速度是小强速度的3倍，那么小强从家到学校共用多少时间？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 + 5</gadget>
<output>20</output>

<result>20</result>