The aunt has a sum of money, which can be used to buy 20 coats alone, and 30 pairs of trousers. How many sets of clothes like this can you buy with this amount of money?
阿姨有一笔钱，单独用来买上衣可以买20件，单独用来买裤子可以买30条．这笔钱可以买多少套这样的衣服？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/20) + (1/30)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / (1/12)</gadget>
<output>12</output>

<result>12</result>