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AP EAMCET202422 May 2024Evening ShiftMathematicsApplication of DerivativesActual

If a man of height 1.8 mt . is walking away from the foot of a light pole of height 6 mt . with a speed of 7 km per hour on a straight horizontal road opposite to the pole, then the rate of change of the length of his shadow is (in kmph)

Options

  1. A7
  2. B5
  3. C3
  4. D2

Correct answer

C. 3

Step-by-step solution

Let OA be the light pole, GF be the man standing at G after time t . In AEF , = 4.2 x In AOB , = 6 x+y 4.2 x = 6 x+y 1.8 x=4.2 y Differentiating w.r.t. t ; 1.8 d x d t =4.2 d y d t 1.8 7 4.2 = d y d t d y d t =3 kmph

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