A clothing store sells a piece of clothing at a profit of 20% of the purchase price, and can earn 50 yuan. However, due to poor business, it sells it at a discount of 10% off the retail price. How much can it earn?
某服装店卖一件衣服，按进价的20%为利润零售可赚50元，但因生意不佳，以零售价打9折出售，可赚多少元．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">50 / (1/5)</gadget>
<output>250</output>

<gadget id="calculator">250 + 50</gadget>
<output>300</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">300 * (9/10)</gadget>
<output>270</output>

<gadget id="calculator">270 - 250</gadget>
<output>20</output>

<result>20</result>