When processing a batch of parts, the ratio of the number completed on the first day to the total number of parts is 1:3, and 40% of this batch of parts can be completed if 30 more parts are made. How many parts are there in total?
加工一批零件，第一天完成的个数与零件总个数的比是1：3，如果再做30个就可完成这批零件的40%．这批零件一共有多少个？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">(2/5) - (1/3)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">30 / (1/15)</gadget>
<output>450</output>

<result>450</result>