2.2 The output of workers at a factory depends on the number of supervisors hired (see below). The factory sells its output for $0.50 each, it hires 50 production workers at a wage of

$100 per day, and needs to decide how many supervisors to hire. The daily wage of supervisors is $500 but output rises as more supervisors are hired, as shown below. How many supervisors should it hire?

Supervisors output (units per day)

0 11,000 1 14,800 2 18,000 3 19,500 4 20,200 5 20,600