Processing a batch of parts, A can process 6 parts per hour, and B can complete the task by processing alone in 4 hours. Now two people cooperate to process this batch of parts. When the task is completed, the ratio of the number of parts processed by A and B is 3:5. How many parts did A process in total?
加工一批零件，甲每小时可加工6个，乙单独加工4小时可以完成任务．现在两人合作加工这批零件，完成任务时，甲、乙两人加工的零件的个数比是3：5．甲一共加工了多少零件？
<gadget id="calculator">5 / 3</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">6 * (5/3) * 4 * (3/8)</gadget>
<output>15</output>

<result>15</result>