A certain courier company has a bunch of goods to be transported. It can be transported 20 times with a large truck and 30 times with a small truck. If the courier company arranges a large truck and a small truck at the same time, how many times can it be delivered? Finished the load?
某快递公司有一堆货物要运走，用一辆大货车20次可以运完，用一辆小货车30次可以运完，如果快递公司安排大货车和小货车各一辆同时运，多少次可以运完这堆货物？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

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

<gadget id="calculator">(1/20) + (1/30)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">1 / (1/12)</gadget>
<output>12</output>

<result>12</result>