For the year ended 31 December 2013, the quantities of units sold are expected to be:

\begin{tabular}{llll}

January & 330 & July & 210 \\

February & 540 & August & 290 \\

March & 310 & September & 510 \\

April & 450 & October & 330 \\

May & 360 & November & 450 \\

June & 300 & December & 570

\end{tabular}

The opening inventory at 1 January 2013 will be 144 units. The closing inventory desired at 31 December 2013 is 150 units.

\section*{Required:}

(a) What will production be per month if an even production flow is required and inventory levels during the year can fall to zero because that minimises the cost of holding inventory?

(b) Given the same information plus the constraint that inventory levels must never fall below 80 units, and that extra production will be undertaken in January 2013 to ensure this happens, what will be the January production figure?