I do not understand why in the matrix you included 900 in X and 800 Y or anything that added is more than 1,200 units per month, as the example 1 said that they cannot carry forward any unsold units in the inventory
Because of what is said in the question. The first line of the question says that the maximum capacity is 1,200 units. Have you not downloaded the free lecture notes (containing the questions) from our website?