Purchasing in logistics $-$ Wagner$-$Within dynamic model

You must make a decision about an article purchasing in your supplier. Demand in your firm for this supply changes in periods $($months$),$ but is known $($table $1).$ Data on cost elements are the following: ordering cost is $c_o=125,-zt,$ unit price in purchasing is $P=30,-zf,$ monthly inventory holding cost rate is $r=2\mathrm{.}5\%$ of price. According to the order, the supply increases inventory nearly immediately $($without a delay at the beginning of the month$)$ and it should allow fulfilling a demand of this period. Initial inventory is $0.$ Determine plan of monthly orders in your supplier $($table $2).$

Table $1.$

Table $2.$

$\backslash$table$[[$Month$,$Period,Demand$],[$January$,1,20],[$February$,2,124],[$March$,3,24],[$April$,4,260],[$May$,5,308],[$June$,6,258],[$July$,7,176],[$August$,8,104],[$September$,9,248],[$October$,10,320],[$November$,11,476],[$December$,12,82],[$Total$,2400]]$

$\backslash$table$[[$Period$,$Initial stock,Demand,Order,Final stock,Total cost$],[1,0,20,,,],[2,,124,,,],[3,,24,,,],[4,,260,,,],[5,,308,,,],[6,,258,,,],[7,,176,,,],[8,,104,,,],[9,,248,,,],[10,,320,,,],[11,,476,,,],[12,,82,,0,],[$Total$,2400,2400,,]]$

Hint: To make ordering decisions calculate the critical point $Q_{cp}=c_d{c}_h$ for ordering decisions.

$Q_{cp}=$dots