The price that a company charges for a basketball hoop is given by the equation [tex]$50 - 5x^2$[/tex] where [tex]$x$[/tex] is the number of hoops produced, in millions. It costs the company [tex]\$30[/tex] to make each basketball hoop. The company recently reduced its production to 1 million hoops but maintained its profit of 15 million dollars. Approximately how many basketball hoops did the company previously produce to make the same profit?

A. 1.3 million hoops
B. 1.4 million hoops
C. 1.5 million hoops
D. 3.0 million hoops



Answer :

To determine how many basketball hoops the company previously produced to make the same profit of [tex]$15$[/tex] million dollars, we can follow these steps:

1. Define Variables and Constants:
- Let [tex]\( x \)[/tex] be the number of basketball hoops produced in millions.
- The price per hoop, [tex]\( P(x) \)[/tex], is given by the equation: [tex]\( P(x) = 50 - 5x^2 \)[/tex] dollars.
- The cost per hoop is [tex]$30. - The profit they maintained is $[/tex]15$ million.

2. Profit Formula:
- Profit is calculated as the difference between the total revenue and the total cost.
- Revenue is given by [tex]\( \text{Revenue} = (\text{Price per hoop}) \times (\text{Number of hoops produced}) \)[/tex].
- Total cost is given by [tex]\( \text{Cost} = (\text{Cost per hoop}) \times (\text{Number of hoops produced}) \)[/tex].

3. Set Up the Profit Equation:
- Using the profit formula, [tex]\( \text{Profit} = \text{Revenue} - \text{Cost} \)[/tex].

[tex]\[ 15,000,000 = \left(50 - 5x^2\right)x - 30x \times 1,000,000 \][/tex]

4. Simplify the Profit Equation:
- Substitute the given conditions and solve for [tex]\( x \)[/tex]:

[tex]\[ \begin{aligned} 15,000,000 &= (50 - 5x^2)x \times 1,000,000 - 30x \times 1,000,000 \\ 15 &= (50 - 5x^2)x - 30x \\ 15 &= 50x - 5x^3 - 30x \\ 15 &= 20x - 5x^3 \end{aligned} \][/tex]

5. Solve the Cubic Equation:
- Rearrange the equation to get all terms on one side:

[tex]\[ 5x^3 - 20x + 15 = 0 \][/tex]

6. Find the Roots:
Since we are solving for [tex]\( x \)[/tex] where [tex]\( x \)[/tex] represents millions of basketball hoops, we are looking for realistic, positive solutions to this equation.

7. Approximate Solution:
We will approximate [tex]\( x \)[/tex] which makes the equation true:
By inspection or using numerical techniques, we can identify that the realistic solution is close to [tex]\( 1.3 \)[/tex] or [tex]\( 1.4 \)[/tex].

After solving the cubic equation, we find that the reasonable solution among the given options is:

[tex]\[ x \approx 1.4 \][/tex]
Therefore, the company previously produced approximately 1.4 million hoops.