batch of fabric can be used to make 12 coats or 15 pairs of trousers. If it is made as a set, at least how many sets of clothes can be made? What is the correct column
一批布料，可做12件上衣或15条裤子，如果成套做，至少可做多少套衣服？正确列式为多少
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/15) + (1/12)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 / (3/20)</gadget>
<output>20/3 = around 6.666667</output>

<result>20/3 = around 6.666667</result>