Final answer:
To find the smallest amount that you can charge and make a profit of at least $393, you need to solve a quadratic inequality. The smallest amount you can charge is approximately $36.19.
Step-by-step explanation:
To find the smallest amount that you can charge and make a profit of at least $393, you need to set up an inequality. The inequality is:
p ≥ 393
Substituting the equation for profit, -0.5x^2 + 36x - 201, into the inequality, we have:
-0.5x^2 + 36x - 201 ≥ 393
Next, rearrange the inequality to solve for x:
-0.5x^2 + 36x - 201 - 393 ≥ 0
-0.5x^2 + 36x - 594 ≥ 0
To solve this quadratic inequality, you can use different methods such as graphing, factoring, or using the quadratic formula. In this case, we can use the quadratic formula:
x = (-b ± √(b^2 - 4ac)) / (2a)
Plugging in the values from the quadratic inequality, we get:
x = (-36 ± √(36^2 - 4(-0.5)(-594))) / (2(-0.5))
Calculating the values inside the square root gives:
x = (-36 ± √(1296 - 1188)) / (-1)
x = (-36 ± √108) / (-1)
Simplifying further gives:
x = -18 ± 3√3
Since we're interested in the smallest amount, we take the smaller value:
x = -18 - 3√3
Therefore, the smallest amount you can charge and make a profit of at least $393 is approximately $36.19.