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The sum of two numbers is 21. 3/4 of one of the numbers added to 2/3 of the other number gives the sum of 15. Find the two numbers

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5 answers

  1. A=12 B=9

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  2. 3/4x+2/3y=15
    --------------------
    y=21-x
    3/4x+2/3(21-x)=15
    3/4x+14-2/3x=15
    9/12x-8/12x=15-14
    1/12x=1
    x=(1/1)/(1/12)
    x=1/1*12/1

    x=12
    -------------------
    3/4*12+2/3y=15
    9+2/3y=15
    2/3y=15-9
    y=6/(2/3)
    y=6*3/2
    y=9
    ---------------
    x+y=21
    12+9=21

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  3. Thank you

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  4. X=12 ,y=9

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  5. a = first number

    b = second number

    The sum of two numbers is 21 means:

    a + b = 21

    3/4 of one of the numbers added to 2/3 of the other number gives the sum of 15 means:

    3 / 4 a + 2 / 3 b = 15

    Now you must solve system of two equations:

    a + b = 21

    3 / 4 a + 2 / 3 b = 15
    ________________

    Try to solve it.

    The solution is:

    a = 12 , b = 9

    Check results:

    a + b = 12 + 9 = 21

    3 / 4 a + 2 / 3 b = 3 / 4 ∙ 12 + 2 / 3 ∙ 9 = 36 / 4 + 18 / 3 = 9 + 6 = 15

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