Teacher Li has to walk 6 kilometers from school to home. The original plan was to ride a bicycle and arrive in 25 minutes. Later, it was changed to walking, which was 120 meters less per minute than cycling. How many minutes does it take Mr. Li to walk home?
李老师从学校到家要行6千米．原计划骑自行车，25分钟可到．后来改为步行，比骑自行车每分钟少行120米．李老师步行到家需要多少分钟？
<gadget id="calculator">6 * 1_000</gadget>
<output>6_000</output>

<gadget id="calculator">6_000 / 25</gadget>
<output>240</output>

<gadget id="calculator">240 - 120</gadget>
<output>120</output>

<gadget id="calculator">6_000 / 120</gadget>
<output>50</output>

<result>50</result>