Price Slope = (change in Price)/(change in quantity) = (40 - 45)/(20 - 10) = -5/10 = -.5
y-intercept = 45 + .5(10) = 50
P is for price
Q is for quantity
Price equation: P = $50 - $0.50Q
Cost Slope = (change in cost)/(change in quantity) = (650 - 450)/(20 -10) = 200/10 = 20
y-intercept = 450 - 20(10) = 250
Cost equation = $250 + $20Q
Revenue equation = Price * Quantity = ($50 - $0.50Q) * Q = 50Q - 0.50Q^2
Profit equation = Revenue - Cost = (50Q - 0.50Q^2) - (250 + 20Q) = -250 + 30Q - 0.50Q^2
Break even point is when revenue equals cost of a certain item
50Q - 50Q^2 = 250 + 20Q
.50Q^2 - 30Q + 250= 0
Q^2 - 60Q + 500 = 0
(Q - 50)(Q - 10) = 0
Q = 50 , Q = 10
When quantity is 10 or 50 items, there is no profit or loss. It breaks even.
Maximized profit
If we use calculus, then we can take a derivative of the profit function to see where it is maximized.
Profit = -250 + 30Q - 0.5Q^2
P' = 30 - Q
30 - Q = 0
Q = 30
The slope goes from positive to negative when it passes through Q=30 which denotes a maximum. Therefore the maximum profit occurs at a quantity of 30. The maximum profit is:
-250 + 30(30) - .50(30)^2 = -250 + 900 - 450 = $200.
Adrian C.
07/01/14