Select all the correct answers.

An electronics store chain sells headphones. The company is about to introduce a new headphone model that is expected to sell very well across various stores. These are the projected revenue and cost functions for the headphones:

[tex]\[
\begin{array}{l}
R(x) = -210 x^2 + 8,970 x \\
C(x) = -170 x + 39,690
\end{array}
\][/tex]

Which two statements are true?

A. The maximum profit is [tex]$\$[/tex] 57,834[tex]$.
B. The maximum profit is $[/tex]\[tex]$ 21,000$[/tex].
C. A selling price of [tex]$\$[/tex] 27[tex]$ results in the maximum profit.
D. A selling price of $[/tex]\[tex]$ 17$[/tex] results in the maximum profit.
E. A selling price of [tex]$\$[/tex] 16.60$ results in the maximum profit.



Answer :

Let's analyze the given functions and the solution step by step for clarity.

The revenue function [tex]\( R(x) \)[/tex] and the cost function [tex]\( C(x) \)[/tex] are given as:
[tex]\[ R(x) = -210x^2 + 8970\pi \][/tex]
[tex]\[ C(x) = -170x + 39690 \][/tex]

To find the maximum profit, we need to determine the profit function [tex]\( P(x) \)[/tex]:
[tex]\[ P(x) = R(x) - C(x) \][/tex]
First, we find the profit function:
[tex]\[ P(x) = (-210x^2 + 8970\pi) - (-170x + 39690) \][/tex]
Simplifying the profit function:
[tex]\[ P(x) = -210x^2 + 8970\pi + 170x - 39690 \][/tex]

To find the critical point where the profit is maximized, we take the first derivative of [tex]\( P(x) \)[/tex] and set it to zero:
[tex]\[ P'(x) = d(-210x^2 + 8970\pi + 170x - 39690) / dx \][/tex]
[tex]\[ P'(x) = -420x + 170 \][/tex]

Setting the first derivative equal to zero to find the critical point:
[tex]\[ 0 = -420x + 170 \][/tex]
Solving for [tex]\( x \)[/tex]:
[tex]\[ x = \frac{170}{420} \approx 0.4048 \][/tex]

Next, we plug this critical value back into the original revenue and cost functions to find the corresponding revenue, cost, and ultimately the profit at this critical point.

Revenue at [tex]\( x = 0.4048 \)[/tex]:
[tex]\[ R = -210 \times (0.4048)^2 + 8970\pi \approx 28145.68 \][/tex]

Cost at [tex]\( x = 0.4048 \)[/tex]:
[tex]\[ C = -170 \times 0.4048 + 39690 \approx 39621.19 \][/tex]

Maximum profit:
[tex]\[ \text{Profit} = R - C = 28145.68 - 39621.19 = -11475.51 \][/tex]

The selling price at this [tex]\( x \)[/tex] is:
[tex]\[ \text{Selling price} = -170 \times 0.4048 + 39690 \approx 39621.19 \][/tex]

Now let's analyze the statements:
- "The maximum profit is \[tex]$57,834." - This statement is false because the maximum profit calculated is approximately -\$[/tex]11,475.51.
- "The maximum profit is \[tex]$21,000." - This statement is false as well for the same reason above. - "A selling price of \$[/tex]27 results in the maximum profit." - This statement is false because the selling price for maximum profit is approximately \[tex]$39,621.19. - "A selling price of \$[/tex]17 results in the maximum profit." - This statement is also false for the same reason above.
- "A selling price of \$16.60 results in the maximum profit." - This statement is false for the same reason above.

None of the statements mentioned above are true based on the given functions and the solution.