SOLUTION: Abby Normal has a pig that presently weighs 200 pounds. She could sell it now for a price of $1.40 per pound. The pig is gaining 5 pounds per week while the price per pound is dr

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: Abby Normal has a pig that presently weighs 200 pounds. She could sell it now for a price of $1.40 per pound. The pig is gaining 5 pounds per week while the price per pound is dr      Log On


   



Question 1158540: Abby Normal has a pig that presently weighs 200 pounds. She could sell it now for a price of $1.40 per pound. The pig is gaining 5 pounds per week while the price per pound is dropping 2 cents per week. When should Abby sell the pig to get the maximum amount of money for it? What is the maximum profit?

Answer by ikleyn(52748) About Me  (Show Source):
You can put this solution on YOUR website!
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Abby Normal has a pig that presently weighs 200 pounds. She could sell it now for a price of $1.40 per pound.
The pig is gaining 5 pounds per week while the price per pound is dropping 2 cents per week. When should Abby
sell the pig to get the maximum amount of money for it? What is the maximum profit?
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The weight as a function of time is

    W(t) = 200 + 5t   pounds

where t is the time in weeks.


The price per pound as a function of time is

    P(t) = 1.40 - 0.02t,


The revenue is

    W*P = (200+5t)*(1.40-0.02t)  dollars    (1)


It is a quadratic function with negative coefficient at the quadratic tem, so the quadratic function has a MAXIMUM.


The function has zeroes at  t= -200%2F5 = -40  and  t= 1.40%2F0.02 = 70.


The maximum of the function is located exactly half-way beteen the zeroes.


So, the maximum is achieved at  t= %28-40%2B70%29%2F2 = 30%2F2 = 15 weeks.


At this value of t, the quadratic function value is  (200+5*15)*(1.40-0.02*15) = 275*1.10 = 302.50  dollars.


ANSWER.  To get the maximum amount of money, Abby should sell the pig in 15 weeks.

         The maximum amount of money will be 302.50 dollars.

Solved.

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Had Abby sold the pig "today", she would get only 200*1.40 = 280 dollars.

Compare it with the found optimal value of 302.50 dollars (!)