A, B, and C make the same number of parts. A makes 20 parts per hour, B makes 24 parts per hour, and C makes 30 parts per hour. When the task is completed, how many parts are made per hour on average.
甲、乙、丙三人做同样多的零件，甲每小时做20个，乙每小时做24个，丙每小时做30个，完成任务时，平均每小时做了多少多少个零件．
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 24</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/20) + (1/24) + (1/30)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">3 / (1/8)</gadget>
<output>24</output>

<result>24</result>