A, B, and C repair a section of road together. A repairs (1/5) kilometers in one day, B repairs (1/10) more than A in one day, and C repairs less (1/20) kilometers in one day than A. , how many kilometers does C repair in a day?
甲、乙、丙三人共修一段路，甲一天修了(1/5)千米，乙一天修的比甲多(1/10)，丙一天修的比甲少(1/20)千米，丙一天修多少千米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/5) - (1/20)</gadget>
<output>3/20 = around 0.15</output>

<result>3/20 = around 0.15</result>