June 26th is the International Anti-Drug Day. The Capital Anti-Drug Association held a long-distance running event with the theme of "promoting a healthy life and all people participating in drug control". Due to the heavy rain that day, only 1,200 students participated in the long-distance running event. There are fewer long-distance running students (1/5). How many students originally planned to participate in the long-distance running? (solution with equation)
6月26日是国际禁毒日，首都禁毒会举办了以"提倡健康人生，全民参与禁毒"为主题的万人长跑活动，由于当天下大雨，只有1200名学生参加了长跑活动，比原计划参加长跑的学生少(1/5)．原计划参加长跑的学生有多少人？(用方程解答)
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1_200 / (4/5)</gadget>
<output>1_500</output>

<result>1_500</result>