For a batch of parts, the number of unqualified products is the number of qualified products (1/19). Later, 2 unqualified products were found out of the qualified products. At this time, the qualified rate of the products is 94%. How many parts are there in this batch?
一批零件，不合格产品数是合格数的(1/19)，后来从合格产品中又发现了2个不合格，这时产品的合格率为94%，这批零件共多少个个．
<gadget id="calculator">19 + 1</gadget>
<output>20</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">94 / 100</gadget>
<output>47/50 = around 0.94</output>

<gadget id="calculator">1 - (1/20) - (47/50)</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">2 / (1/100)</gadget>
<output>200</output>

<result>200</result>