The master and apprentice jointly produce a batch of parts. The master has produced 80 parts, accounting for (4/5) of this batch of parts, and the apprentice has produced (3/20) of this batch of parts. How many parts has the apprentice produced?
师徒两人共同生产一批零件，师傅已经生产了80个，占这批零件的(4/5)，徒弟已经生产了这批零件的(3/20)，徒弟已经生产了多少个零件？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">80 / (4/5)</gadget>
<output>100</output>

<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">100 * (3/20)</gadget>
<output>15</output>

<result>15</result>