The packaged ones are (2/5) of the total number of candies, and if 21 kg are repacked, the packaged ones are exactly (3/4) of the total number of candies. How many kilograms is this batch of candy in total?
已经包装的是糖果总数的(2/5)，再包装21千克，则已包装的正好是糖果总数的(3/4)．这批糖果一共有多少千克？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">21 / (7/20)</gadget>
<output>60</output>

<result>60</result>