How to find those numbers

Gaudi is a retailer for overhead water tanks that are available in three different capacities 2000 liters, 3000 liters, and 4000 liters. The table shows the inventory parameters of these water tanks. If Gaudi has a space limitation of 3500 cubic feet in their showroom, determine the optimal order quantities for these water tank models that will satisfy the space constraint.

Use possible value of in the range [0.20 and 0.30]

Table 7.5 Values for and optimal lot sizes