2-23 A firm believes a product's sales volume (S) depends on its unit selling price (P) as S = $100- P. The production cost (C) is $1000 + 10S. (a)

Graph the sales volume (S) from 0 to 100 on the x axis, total cost and total income from $0 to$2500 on the y axis, C = $1000+ 10S, and plot the curve of total income. Mark the breakeven points on the graph. (b) Determine the break even point (lowest sales volume at which total sales income just equals total production cost). (c) Determine the sales volume (S) at which the firm's profit is a maximum.