A project, after 6 days of joint work by teams A and B, 2/5 of the project remains. How many days will it take for the two teams to work together on the rest of the project?
一项工程，由甲，乙两队合做6天后，还剩下这项工程的2/5．两队合做剩下的工程还需要多少天？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) / 6</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(2/5) / (1/10)</gadget>
<output>4</output>

<result>4</result>