In a pack of sugar, toffee accounts for 9/20 of the total, and then 16 pieces of fruit candy are put in. At this time, toffee accounts for 25% of the total. How many pieces of toffee are there?
一包糖，奶糖占总数的(9/20)，后又放入16块水果糖，这时奶糖占总数的25%，有奶糖多少块？
<gadget id="calculator">9 / 20</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(9/20) / (1/4)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">(9/5) - 1</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">16 / (4/5)</gadget>
<output>20</output>

<gadget id="calculator">20 * (9/20)</gadget>
<output>9</output>

<result>9</result>