A bag of flour, eating the whole bag (2/5), is exactly 20 kg. How many kilograms does this bag of flour weigh? (Write out the quantitative relationship first, then answer).
一袋面粉，吃了全袋的(2/5)，正好是20千克．这袋面粉重多少千克？(先写出数量关系，再解答)．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 / (2/5)</gadget>
<output>50</output>

<result>50</result>