The average of a number and double the number is 25.5

Discussion in 'Calculator Requests' started by math_celebrity, Oct 22, 2016.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    Let x equal "a number".

    Double the number is 2x.

    The average is (x + 2x)/2

    Combine the terms in the numerator:

    The word is means equal to, so we set 3x/2 equal to 25.5
    3x/2 = 25.5

    Cross multiply the 2:
    3x = 51

    Divide each side by 3
    x = 17

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