In the construction of the road around the lake, there is a pile of concrete weighing 50 tons. One car transported away (1/5) for the first time and 25% for the second time. How many tons are left?
环湖公路建设中有一堆重50吨的混凝土，一辆汽车第一次运走(1/5)，第二次运走25%．还剩多少吨？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">25 / 100</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>