Question

Models of inventory systems frequently consider therelationships among a beginning inventory, a production quantity, ademand or sales, and an ending inventory. For a given productionperiod j, let

S_j−1

=

beginning inventory for period j (ending inventoryfrom period j − 1, the previous period)

x_j

=

production quantity in period j

d_j

=

demand in period j

S_j

=

S_j =ending inventory for period j

Choose the correct mathematical relationship or model that showsending inventory as a function of beginning inventory, production,and demand.

(1)	Sj =Sj−1 − xj− dj
(2)	Sj =Sj−1 + xj− dj
(3)	Sj−1 =Sj + xj −dj
(4)	Sj−1 =Sj − xj −dj

What constraint should be added if production capacity for periodj is given by Cj? Choose the correct answer.

(1)	xj ≥Cj
(2)	xj ≤Cj
(3)	dj ≥Cj
(4)	dj ≤Cj

What constraint should be added if inventory requirements forperiod j mandate an ending inventory of at leastI_j? Choose the correct answer.

(1)	Sj ≥Ij
(2)	Sj ≤Ij
(3)	Sj-1 ≥Ij
(4)	Sj-1 ≤Ij