A worker who processes parts is paid 2 yuan for each genuine product produced, and is fined 5 yuan for each defective product produced. One day, the authentic products he processed were 7 times that of the defective ones, and he earned 54 yuan. How many defective products did he produce that day?
某工人加工零件，每加工出一个正品得报酬2元，每出一个次品罚款5元．一天他加工的正品是次品的7倍，得款54元．这天他制出了多少件次品．
<gadget id="calculator">2 * 7</gadget>
<output>14</output>

<gadget id="calculator">14 - 5</gadget>
<output>9</output>

<gadget id="calculator">54 / 9</gadget>
<output>6</output>

<result>6</result>