Guangdong Beijiang Middle School was entrusted by the superior to organize this year's Shaoguan City Tour Guide Qualification Examination. There are 50 examination rooms to be set up in the examination room. Each examination room needs 2 invigilators, and several staff members are required for the entire examination room. It is known that each examination room requires an average 2.4 people, Q: In addition to the invigilator, how many other staff should be arranged?
广东北江中学受上级委托组织今年的韶关市导游资格考试，考场准备设50个考室，每个考室需2名监考员，整个考场另需若干名工作人员，已知每个考室平均需要2.4人，问：除了监考员以外，另需安排多少名工作人员？
<gadget id="calculator">50 * 2.4</gadget>
<output>120</output>

<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">120 - 100</gadget>
<output>20</output>

<result>20</result>