The garment factory processed a batch of garments. After processing 3,000 pieces, the work efficiency increased to 2.5 times due to improved technology and strengthened cooperation. Then another 3,000 pieces were produced, and it was found that it took 18 days less than before. How many pieces were produced per day before the technology was improved?
服装厂加工一批服装，加工了3000件后，由于改过了技术，并加强了合作，使得工作效率提高到了原来的2.5倍．接着又生产了3000件，这时发现比原来少用了18天．改进技术前每天生产多少件？
<gadget id="calculator">3_000 * 2.5</gadget>
<output>7_500</output>

<gadget id="calculator">7_500 - 3_000</gadget>
<output>4_500</output>

<gadget id="calculator">18 * 2.5</gadget>
<output>45</output>

<gadget id="calculator">4_500 / 45</gadget>
<output>100</output>

<result>100</result>