Beach Day by Rodger Bliss
September 2022
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Princess Bride

A princess is as old as the prince will be when the princess is twice the age that the prince was when the princess’s age was half the sum of their present ages. What are their ages?

 

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3 guesses to Princess Bride


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  • Roolstar

    X = Princess’ age
    Y = Prince’s age
    (Think genetics XY / XX)

    X = Y + 2 {Y – [ (X + Y)/2 – Y]} – X
    2X = Y + 2{ Y – [X/2 – Y/2]}
    2X = Y + 2{ 3Y/2 -X /2}
    2X = Y +3Y -X
    3X =4Y

    Any ages in these proportions would work…

    Princess: 4 – 8 – 12 – 16 – 20 …
    Prince: 3 – 6 – 9 – 12 – 15 …

    Let’s take Princess 16 and Prince 12

    Half the sum of their ages = 14
    When the princess was “Half the sum of their ages” = 14 – 12 = 2 years ago
    The princes age “when the princess was Half the sum of their ages” = 12 – 10 = 10 years old
    Twice “The prince’s age was when the princess was Half the sum of their ages” = 10 x 2 = 20
    The princess will be 20 in 4 years
    The prince’s age will then be 12 +4 = 16 by then = the current age of the princess (PERFECT)

  • Dude

    Great answer, Rool!

    We came up with this one:

    Princess: a
    Prince: b
    0.5*(a+b) a – (0.5*(a+b)) = 0.5*a-0.5*b b – (0.5*a-0.5*b) = 1.5*b-0.5*a 3*b-a
    (3*b-a) – a = 3*b-2*a b + (3*b-2*a) = 4*b-2*a a = 4*b-2*a or 3*a = 4*b b+10
    0.5*b+5 b – (0.5*b+5) = 0.5*b-5 a – (0.5*b-5) = a-0.5*b+5 b = a-0.5*b+5 or a = 1.5*b-5
    Now we have two equations:
    3*a = 4*b and a = 1.5*b-5.
    Substitute “a” in the first equation for the value of “a” from the second equation:
    3*(1.5*b-5) = 4*b
    Solving this equation, we get:
    b=30
    Since a = 1.5*b-5:
    a=40

    So the princess was 40 and the prince was 30 in this scenario.

    You’re today’s winner.

  • Tring tring

    The relation comes out to y=(4/3)x
    Where x- prince’s age
    And y – princess’s age

    So there are many possibilities of the answers.
    It could be x = 30 and y=40