Master Zhang processed a batch of parts. On the first day, he processed 25% of this batch of parts. If he processed 30 more parts, the ratio of the processed parts to the total number of this batch of parts is exactly 2:3. How many parts are there in this batch? ?
张师傅加工一批零件，第一天加工了这批零件的25%，如果再加工30个，已经加工的零件和这批零件总数的比就刚好是2：3，这批零件一共有多少个？
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

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

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

<gadget id="calculator">(2/5) - (1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">30 / (3/20)</gadget>
<output>200</output>

<result>200</result>