Formula to calculate hours work to determine if I need to hire more staff

[Pinkberry]

I have 200,000 items processed for the month (20 working days). Each process takes 3 mins to perform. So I got the hours down which is 200,000 x 3 /60. If I have 5 employees each working 8 hours a day 5 days a week, what is the formula to know if I have enough employees to process this task. The end result is that I want to make sure the employees are not doing overtime and to hire more employees if needed.
Thank you in advance

 

[yogeshmaney]

u hv 200000 Processes in 20 work days
i.e 10000 Proc in a day
each proc is of 3 min
so for 10000 proc u need 30000 work min


1 person has 8 work hrs so 8x60 wrk min
so 1 person can do 160 proc in a day


So to perform 10000 proc

u need 10000/160 persons i.e 62.5