A project can be completed in 30 days by the cooperation of teams A and B. After 24 days of working alone, teams A and B cooperate for another 12 days. Then A was transferred away, and B worked for another 15 days to complete all the projects. How many days does it take Team A to complete this project alone?
一项工程，甲、乙两队合作30天可完成，甲队独做24天后，甲乙两队又合作了12天．然后甲调走，乙又做了15天才完成了全部的工程．甲队单独做这项工程需要几天完成？
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">12 + 15</gadget>
<output>27</output>

<gadget id="calculator">(1/30) * 27</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">12 - 27</gadget>
<output>-15</output>

<gadget id="calculator">24 + (-15)</gadget>
<output>9</output>

<gadget id="calculator">(1/10) / 9</gadget>
<output>1/90 = around 0.011111</output>

<gadget id="calculator">1 / (1/90)</gadget>
<output>90</output>

<result>90</result>