It takes 3 hours for the two masters and apprentices to process a batch of parts, but the master alone can complete it in 2 hours (1/2). It is known that the master processes 30 more parts per hour than the apprentice, how many parts are there in total?
师徒两人共加工一批零件要3小时完成，师傅单独加工2小时可以完成(1/2)．已知师傅每小时比徒弟多加工30个，这批零件共有多少个？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) / 2</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/4) - (1/12)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">30 / (1/6)</gadget>
<output>180</output>

<result>180</result>