A bucket of peanut oil weighs 50kg, 20% of the total is sold on the first day, and 1/4 of the total is sold on the second day, how many kilograms are left?
一桶花生油重50kg，第一天售出了总数的20%，第二天售出总数的(1/4)，还剩下多少千克？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">50 * (11/20)</gadget>
<output>55/2 = around 27.5</output>

<result>55/2 = around 27.5</result>