To answer this item, we let x be the number of employees and y be the pay each day of each of the employee. Currently, the payroll is equal to xy. The equations that would best represent the given situation above are,
(x + 50)(y - 2) = xy + 620
and (x - 50)(y + 4) = xy - 640
The values of x and y in the equations can be calculated through elimination or substitution method.
The values are 140 and 20, respectively. Thus, there are 140 employees currently.