The two masters and apprentices work together to process 360 parts. The two can complete it in 6 days, and the apprentice can complete it in 15 days. If the master does it alone, how many days can it be completed?
师徒二人共同加工360个零件，两人合做6天可以完成，徒弟单独做15天可完成，如果由师傅单独做多少天可以完成？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/6) - (1/15)</gadget>
<output>1/10 = around 0.1</output>

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

<result>10</result>