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MHT CET · Maths · Application of Derivatives

The edge of a cube is decreasing at the rate of 0.04 cm/sec. If the edge of the cube is 10 cms, then rate of decrease of surface area of the cube is …

  1. A 4.8cm2sec
  2. B 4.08cm2sec
  3. C 48cm2sec
  4. D 4.008cm2sec
Verified Solution

Answer & Solution

Correct Answer

(A) 4.8cm2sec

Step-by-step Solution

Detailed explanation

Let edge of a cube be x cm, then surface area of the cube, A=6x2
It is given that, dxdt=-0.04 cm/sec
Now, dAdt=12xdxdt
=12x-0.04
=-0.48x
when, x=10, then dAdt=0.48×10=-4.8cm2sec