The garment factory receives the task of processing a batch of garments. Master Wang can make 3 sets of clothes every day, and Master Li can make 5 sets of clothes every day. If Master Wang completes the task of making this batch of clothing alone, it will take 4 more days than Master Li alone to complete the task of making this batch of clothing. So, how many sets of this batch of clothes are to be processed?
服装厂接到加工一批服装的任务，王师傅每天可以制作3套服装，李师傅每天可以制作5套服装．如果王师傅单独完成制作这批服装的任务，比李师傅单独完成制作这批服装的任务要多用4天．那么，要加工的这批服装共有多少套．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/3) - (1/5)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">4 / (2/15)</gadget>
<output>30</output>

<result>30</result>