project, A and B work together to complete (1/6) of the whole project every hour, if A first works for 4 hours, and B works for another 3 hours, the remaining (2/5) of the whole project has not been completed. How many hours would it take for A to complete the project independently?
一项工程，甲、乙合做每小时完成全工程的(1/6)，如果甲先做4小时，乙再做3小时，还剩全工程的(2/5)没有完成．若由甲独立完成该工程要多少小时？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/6) * 3</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (2/5) - (1/2)</gadget>
<output>1/10 = around 0.1</output>

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

<result>10</result>