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  • Aug 18, 2013, 09:31 PM
    dibyarmohapatra
    Arithmetic Progression
    A and b are 2 numbers whose arithmetic mean is 25 and geometric mean is 7... Which of the following may be the value of A?

    • 10
    • 25
    • 49
    • 25
  • Aug 18, 2013, 09:33 PM
    J_9
    This site prohibits us from doing your homework for you. You will have to show us that you have come to an answer, and why, before we will help you.
  • Aug 18, 2013, 09:37 PM
    dibyarmohapatra
    I tried the method like
    A+B/2 = 25,
    so A+B= 50


    sqrt(AB)= 7

    So AB=49

    (A+B)^2= A^2 + B^2 + 2AB= A^2 + B^2 + 98 = 2500

    Can't Understand what to do next to find the value of A?
  • Aug 19, 2013, 05:55 AM
    ebaines
    If AB=49, then A = 49/B.

    You also know that A+B=50, so substitute the value for A from above to get (49/B)+B=50. Now if you multiply through both sides by B you will get a quadratic equation that you can factor. Try it and see - let us know what you get for an answer.

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