Using constant workforce and varying inventory and stock out, what would be the constant workforce? Production required in periods $1,2$ and $3$ respectively are $1,200,1,500$ and $900$ units. One worker during the panning horizon can produce two units in one day. Number of workdays are $22$ in period $1,17$ in period $2,$ and $21$ in period $3.$ Assume that the beginning inventory is $300$ units. What is the number of workers required during the planning horizon of three periods?

Total production required $=$ Total demand during the three period $+$ ending inventory required beginning inventory $=1,200+1,500+900-300=3,300.$ Number of workdays available $=22+17+21=60$ days. One worker can produce $602=120$ units during the planning horizon. So number of workers needed to produce $3,300$ units $=3,\frac{300}{120}=27\mathrm{.}5.$ Rounded up $=28$ workers.