It takes 20 days for team A to build a canal and 30 days for team B to do it alone. If the two teams cooperate, their work efficiency will be reduced due to the influence of each other's construction. Team A's work efficiency becomes four-fifths of the original, and team B's work efficiency is only nine-tenths of the original. Now it is planned to complete the canal in 16 days, and the number of days for the two teams to cooperate is as few as possible, so how many days will the two teams cooperate?
修一条水渠，单独修，甲队需要20天完成，乙队需要30天完成．如果两队合作，由于彼此施工有影响，他们的工作效率就要降低．甲队的工作效率变为原来的五分之四，乙队的工作效率只有原来的十分之九．现在计划16天修完这条水渠，且要两队合作的天数尽可能少，那么两队要合作几天？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * 16</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">7 / 100</gadget>
<output>7/100 = around 0.07</output>

<gadget id="calculator">(7/100) - (1/20)</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/5) / (1/50)</gadget>
<output>10</output>

<result>10</result>