The school plans to process 600 sets of desks and chairs. A said: "Our team contracted, and we can complete the task in 15 days." B said: "Our team contracted, and we can complete the task in 12 days." The school decided to let the two teams work together. How many days can we complete the task?
学校计划加工600套课桌椅．甲说："我们队承包，15天能完成任务．"乙说："我们队承包，12天能完成任务．"学校决定让两个队一起加工，这样多少天能完成任务？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/15) + (1/12)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 / (3/20)</gadget>
<output>20/3 = around 6.666667</output>

<result>20/3 = around 6.666667</result>