SOLUTION: Brooklyn has a summer window washing business. Based on experience Brooklyn knows that P= - 2x² + 130x - 1500 models her profit, P, in dollars, where x is the amount she charg

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: Brooklyn has a summer window washing business. Based on experience Brooklyn knows that P= - 2x² + 130x - 1500 models her profit, P, in dollars, where x is the amount she charg      Log On


   



Question 1203125: Brooklyn has a summer window washing business. Based on experience Brooklyn knows that P= - 2x² + 130x - 1500 models her profit, P, in dollars, where x is the amount she charges per window. How much must Brooklyn charge to maximize her profit? What is the maximum profit?

Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
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Brooklyn has a summer window washing business. Based on experience
Brooklyn knows that P= - 2x² + 130x - 1500 models her profit, P, in dollars,
where x is the amount she charges per window.
(a) How much must Brooklyn charge to maximize her profit?
(b) What is the maximum profit?
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They want you find the maximum of the quadratic function P(x) = -2x^2 + 130x - 1500.


It is well known fact that a quadratic function f(x) = ax^2 + bx + c gets its maximum value at  

              x%5Bmax%5D = -b%2F%282a%29.


In your case,  a= -2, b= 130,  therefore,  x%5Bmax%5D = -130%2F%282%2A%28-2%29%29 = 130%2F4 = 32.50 dollars.


The maximum profit is then  P(32.50) = -2*32.50^2 + 130*32.50 - 1500 = 612.50 dollars.


ANSWER.  (a) $32.50;  (b) $612.50.

Solved.

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On finding the maximum/minimum of a quadratic function see the lessons
    - HOW TO complete the square to find the minimum/maximum of a quadratic function
    - Briefly on finding the minimum/maximum of a quadratic function
    - HOW TO complete the square to find the vertex of a parabola
    - Briefly on finding the vertex of a parabola

Consider these lessons as your textbook,  handbook,  tutorials and  (free of charge)  home teacher.
Learn the subject from there once and for all.