Number of droids 0, 1, 2, 3, 4, 5 Output of moisture (barrels per month) 0, 25, 45, 60, 70, 75

Luke Skywalker's Uncle Owen operates a moisture farm on the planet Tatooine. The moisture farm utilizes droids as a resource to produce the moisture. Owen's production function is given in the accompanying table. If a barrel of moisture sells for 60 Republic Credits and a droid costs 800 Republic Credits per month to rent, how many droids should Owen rent?