Kendra is half as old as Morgan and 3 years younger than Lizzie. The total of their ages is 39. How

Discussion in 'Calculator Requests' started by math_celebrity, Apr 12, 2019.

  1. math_celebrity

    math_celebrity Administrator Staff Member

    Kendra is half as old as Morgan and 3 years younger than Lizzie. The total of their ages is 39. How old are they?

    Let k be Kendra's age, m be Morgan's age, and l be Lizzie's age. We're given:
    1. k = 0.5m
    2. k = l - 3
    3. k + l + m = 39
    Rearranging (1) by multiplying each side by 2, we have:
    m = 2k

    Rearranging (2) by adding 3 to each side, we have:
    l = k + 3

    Substituting these new values into (3), we have:
    k + (k + 3) + (2k) = 39

    Group like terms:
    (k + k + 2k) + 3 = 39
    4k + 3 = 39

    Type this equation into the search engine, and we get:
    k = 9

    Substitute this back into (1), we have:
    m = 2(9)
    m = 18

    Substitute this back into (2), we have:
    l = (9) + 3
    l = 12
     

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