ExamBro
ExamBro
CUET · MATHS · PYQ PAPER 2025

The total cost function is given by \(C(x)=\frac{1}{3} x^3-5 x^2+30 x-15\) and selling price per unit is Rs. 6. The profit is maximum if the value of x is:

  1. A x = 4
  2. B x = 6
  3. C x = 5
  4. D x = 10
Verified Solution

Answer & Solution

Correct Answer

(B) x = 6

Step-by-step Solution

Detailed explanation

\(R(x) = 6x\) \(P(x) = R(x) - C(x) = 6x - (\frac{1}{3} x^3-5 x^2+30 x-15) = -\frac{1}{3} x^3 + 5 x^2 - 24 x + 15\) \(P'(x) = -x^2 + 10x - 24\) \(P'(x) = 0 \Rightarrow -x^2 + 10x - 24 = 0 \Rightarrow x^2 - 10x + 24 = 0 \Rightarrow (x-4)(x-6) = 0\) \(x = 4\) or \(x = 6\)…