garment factory produces a batch of sportswear in September, and the ratio of the number of sets completed in the first 10 days to the number of unfinished sets is 1:3. If another 300 sets are produced, the number of remaining sets is exactly (3/5) of this batch of sportswear. How many sets of this batch of sportswear are there in total?
某服装厂九月份生产一批运动服，前10天完成的套数与未完成套数的比是1：3．如果再生产300套，剩下的套数正好是这批运动服的(3/5)，这批运动服共多少套？
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

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

<gadget id="calculator">300 / (3/20)</gadget>
<output>2_000</output>

<result>2_000</result>