A new set of classical classic "Romance of the Three Kingdoms" has arrived in the bookstore, priced at 50 yuan. In order to promote sales, the bookstore decided to sell each set at a reduced price (1/5). How much is it cheaper if you buy two sets?
书店新到一套古典名著《三国演义》，定价50元，为了促销，书店决定每套降价(1/5)出售．如果买上两套，共便宜多少元？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">50 * (1/5) * 2</gadget>
<output>20</output>

<result>20</result>