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CUET · MATHS · PYQ PAPER 2023

If \(V=\frac{4 \pi r^3}{3}\), at what rate in cubic units \(/ sec\) is V increasing when \(r=10\), and \(\frac{d r}{d t}=0.01 ?\)

  1. A \(\pi\)
  2. B \(4 \pi\)
  3. C \(40 \pi\)
  4. D \(4 \pi / 3\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(4 \pi\)

Step-by-step Solution

Detailed explanation

\(\frac{dV}{dt} = 4 \pi r^2 \frac{dr}{dt}\) \(\frac{dV}{dt} = 4 \pi (10)^2 (0.01)\) \(\frac{dV}{dt} = 4 \pi (100) (0.01) = 4 \pi\)