Answer:
10,000 pPhones.
Step-by-step explanation:
The cost to manufacture x pPhones is given by the cost function:
[tex]C(x)=-25x^2+49000x+21390[/tex]
And the revenue for selling x pPhones is given by the revenue function:
[tex]R(x)=-29x^2+129000x[/tex]
We want to determine the number of pPhones the Pear Company should sell to maximize profits.
First, we can find the profit function. Profit is given by:
[tex]P(x)=R(x)-C(x)[/tex]
Therefore:
[tex]P(x)=(-29x^2+129000x)-(-25x^2+49000x+21390)[/tex]
Simplify:
[tex]P(x)=(-29x^2+129000x)+(25x^2-49000x-21390)[/tex]
Add. So, our profit function is:
[tex]P(x)=-4x^2+80000x-21390[/tex]
Note that our profit function is a quadratic. The maximum point of a quadratic is always its vertex. So, we can find the vertex of the profit function.
The coordinate of the vertex is given by:
[tex]\displaystyle \Big(-\frac{b}{2a},f\Big(-\frac{b}{2a}\Big)\Big)[/tex]
In this case, a = -4, b = 80000, and c = - 21390.
Therefore, the point at which profit is maximized is:
[tex]\displaystyle x=-\frac{80000}{2(-4)}=-\frac{80000}{-8}=10000[/tex]
Therefore, in order to maximize profits, the Pear Company should sell exactly 10,000 phones.
Notes:
And the maximum profit will be:
[tex]P(10000)=-4(10000)^2+80000(10000)-21390=\$399,978,610[/tex]