A certain project is completed in 20 days by the cooperation of teams A and B, and 30 days by team A alone. Now after 6 days of cooperation between the two teams, the rest will be completed by team A. How many days will it take?
某项工程甲乙两队合作20天完成，甲队单独做30天完成，现在两队合作6天后，剩余的由甲队完成，还要多少天？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * 6</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

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

<gadget id="calculator">(7/10) / (1/30)</gadget>
<output>21</output>

<result>21</result>