The little sloppy forgot to bring his schoolbag to school. When his father found out, he rode his bicycle to chase after him, and returned home immediately after handing the schoolbag to him. After the little sloppy received the schoolbag, he walked for another 10 minutes to reach the school, and his father happened to be home at this time. If the father's speed is 4 times the speed of the little sloppy, how much time does it take the little sloppy to go from home to school?
小马虎上学忘了带书包，爸爸发现后立即骑车去追，把书包交给他后立即返回家．小马虎接到书包后又走了10分钟到达学校，这时爸爸也正好到家．如果爸爸的速度是小马虎速度的4倍，那么小马虎从家到学校共用多少时间？
<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">40 + 10</gadget>
<output>50</output>

<result>50</result>