Grandmother, mother and daughter are celebrating 150 years of life. The Mother is 25 years older tha

Discussion in 'Calculator Requests' started by math_celebrity, Jun 1, 2020.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    Grandmother, mother and daughter are celebrating 150 years of life. The Mother is 25 years older than her daughter, but 31 years younger than her mother (the grandmother). How old are the three

    Let grandmother's age be g. Let mother's age be m. Let daughter's age be d. We're given 3 equations:
    1. m = d + 25
    2. m = g - 31
    3. d + g + m = 150
    This means the daughter is:
    d = 25 + 31 = 56 years younger than her grandmother. So we have:
    4. d = g - 56

    Plugging in equation (2) and equation(4) into equation (3) we get:
    g - 56 + g + g - 31

    Combine like terms:
    3g - 87 = 150

    Typing this equation into the search engine, we get:
    g = 79

    Plug this into equation (2):
    m = 79 - 31
    m = 48

    Plug this into equation (4):
    d = 79 - 56
    d = 23
     

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