A certain unit buys personal accident insurance for all employees, and the insurance amount per person is 4,000 yuan. If the annual insurance premium rate is 0.5%, and the total insurance premium paid in the past two years is 9,600 yuan, how many employees in this unit have participated in the insurance?
某单位为全体职工买了人身意外伤害保险，每人保险金额是4000元，如果每年的保险费率是0.5%，两年来共交保险费9600元，这个单位共有多少职工参加保险？
<gadget id="calculator">0.5 / 100</gadget>
<output>0.005</output>

<gadget id="calculator">4_000 * 0.005 * 2</gadget>
<output>40</output>

<gadget id="calculator">9_600 / 40</gadget>
<output>240</output>

<result>240</result>