The problem states that there are 18,600 employees, and that 121 leave voluntarily. There are 18,479 employees
The problem therefore is asking us the number of employees they have if they fire 3% of them.
To find three percent of 18,479, multiply by 0.97 to remove 3 percent.
17924.64.
Since you can't have 0.64 of an employee, round up.
17925
Subtract 17925 from 18497.
572
572 employees must be laid off