Processing a batch of parts, A alone takes 15 days, and B alone takes 10 days to complete. When A and B work together at the same time, A makes 2400 parts. How many parts are there in total?
加工一批零件，甲单独做要15天，乙单独做要10天完成，甲乙同时全合做完成时，甲做了2400个，这批零件共有多少个？
<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">2_400 / (2/15)</gadget>
<output>18_000</output>

<result>18_000</result>