9 people from Class 1 participated in the planting interest group, which happened to be 1/5 of the whole class. How many students are there in Class 1?
六1班有9人参加了种植兴趣小组，正好是全班人数的(1/5)，六1班有学生多少人．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">9 / (1/5)</gadget>
<output>45</output>

<result>45</result>