A company produces and sells x electronic devices per week, where 0<x<200. Its weekly revenue (in dollars) is R(x)=100x−0.5x2, and its weekly cost is C(x)=20x+1000. The profit earned
per device is P(x)=xR(x)−C(x). For what number of devices x is the profit per device maximized?
a) 80
b) 32
c) 45
d) 100