JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2011

  • question_answer
        Let two numbers have arithmetic mean 9 and geometric mean 4. Then, these numbers are the roots of the quadratic equation

    A)  \[{{x}^{2}}+18x-16=0\]

    B)  \[{{x}^{2}}-18x+16=0\]

    C)  \[{{x}^{2}}+18x+16=0\]

    D)  \[{{x}^{2}}-18x-16=0\]

    Correct Answer: B

    Solution :

                    Let the two numbers be\[\alpha \]and\[\beta ,\]then \[\frac{\alpha +\beta }{2}=9\]and\[\alpha \beta ={{4}^{2}}=16\] \[\therefore \]Required equation is\[{{x}^{2}}-(\alpha +\beta )+\alpha \beta =0\] \[\therefore \]  \[{{x}^{2}}-18x+16=0\]


You need to login to perform this action.
You will be redirected in 3 sec spinner