Since the number of employees increased by 4%, then, find what is 4% of 389 equal to. That corresponds to the amount of new employees.
To find what is 4% of 389, multiply 389 by 4/100:

Rounded to the nearest whole number, there are 16 new employees.
Add 16 to 389 to find the total amount of employees this year:

Therefore, the number of employees this year is 405.