project is to be done alone. A needs 10 days to complete, and B takes 15 days to complete. At the beginning, the two work together. Due to work needs, A is transferred halfway. As a result, B and B took 9 days to complete. How many days did Team A transfer away?
一项工程，单独做，甲要10天完成，乙要15天完成，开始二人一起干，因工作需要甲中途调走，结果乙一共用了9天完成．甲队中途调走了几天？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/15) * 9</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

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

<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<result>5</result>