It takes 20 days for team A to do it alone, 15 days for team B to do it alone, and 18 days for team C to do it alone. What percentage of the work can be completed by the three teams working together in one day?
一项工程，甲队单独做需20天，乙队单独做需15天，丙队单独做需18天，三队合做一天可以完成这项工作的几分之几？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">(1/20) + (1/15) + (1/18)</gadget>
<output>31/180 = around 0.172222</output>

<result>31/180 = around 0.172222</result>