Maximin, maximax

Hi. my question is related to question #25 Stow Health, in the Becker exam kit. i have 1 question in it: first, how do we know that the given range of variable costs are applied to each invoice value? i just assumed that that each var. cost corresponded to each value: 70 to 180, 85 to 200 and 95 to 220. i guess i am asking how are we to discern this? when it said 9 possible outcomes, i figured 3 invoice values and 3 occupancy levels give 9! pls help