Projected demand for a companys products is shown. On average an employee can complete $5$ units$/$day based on $40$ hours$/$week$,$ and inventory at the beginning of period $1$ equals zero $($each question below is independent of others$).$ a$.$If a chase plan is used with hiring and firing, how many operators will be required in period $1$ if there is a requirement to have ending inventory each period equal to $10$ days of supply?