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NDA2021MathematicsQuadratic EquationActual

If x+y=20 and P=x y , then what is the maximum value of P ?

Options

  1. A100
  2. B96
  3. C84
  4. D50

Correct answer

A. 100

Step-by-step solution

x+y=20 and P=x y A.M. of x and y= x+y 2 = 20 2 =10 . G.M. of x and y= x y = P As, A.M. G.M. 10 P Hence, P_ . =(10)^2=100 .

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