Mr. P is 76, and his granddaughter is 12.  In how many years will Mr. P. be 5 times as old as his granddaughter?  Thank you!?

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  • 5 months ago
    Favourite answer

    Let n be the number of years until that happens.

    Mr. P's age will be 76 + n

    His granddaughter will be 12 + n

    You want the first amount to be 5 times the second amount:

    76 + n = 5(12 + n)

    Distribute:

    76 + n = 60 + 5n

    Subtract 60 from both sides and also subtract n from both sides:

    76 - 60 = 5n - n

    16 = 4n

    Divide both sides by 4 to isolate n:

    n = 16/4

    n = 4

    Double-check the answer.

    In 4 years, Mr. P will be 80

    In 4 years, his granddaughter will be 16

    5 * 16 = 80

    Answer:

    This will happen in 4 years

  • Mr. P
    Lv 7
    5 months ago

    I feel old            .

  • 5 months ago

    @Puzzling's answer is excellent, as usual.

    Just for fun, here is how I thought about it, without using pencil and paper.

    Mr. P is so old, that adding a few years to his age isn't going to change his age much.  His grandaughter is young, however, so any additions to her age matter a lot, in finding the ratio of their ages.  So I'm going to divide Mr. P's current age by 5 to find out approximately how old his granddaughter would need to be.  76 isn't evenly divisible by 5, so I'll go with 75, which is.  75/5 = 15, so that's my first guess.  3 years from now, his granddaughter will be 15.  But if I add 3 to 76, the answer isn't a multiple of 5.  So I'll try adding 4, and by luck, that works out.  My next guess would have been adding 9, and if that didn't work, I'd go back to pencil and paper.

  • 5 months ago

    5 x 16 = 80, so I will guess 4 {If he is not dead.}

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  • 5 months ago

    let x number of years that MR. P  be 5 times as his granddaughter. 

    76 + x = 5(x + 12)

    76 + x = 5x + 60

    x - 5x = 60 - 76

     -4x = - 16

     x = 4 years   Answer//

  • 5 months ago

    LET THE NO OF YEARS TAKEN FOR MR P TO BECOME 5 TIMES HIS GRANDDAUGHTER'S AGE BE  X YEARS

     (76 +X) / (12 +X) =  5/1

    CROSS MULTIPLY

    5 (12 +X) = 76 +X

    5X -X = 16

    4X =16

    X = 4 YEARS ANSWER

    CHECK

    76+4 = 80

    12+4 =16

    80/16 = 5

  • DWRead
    Lv 7
    5 months ago

    Solve for n:

    76+n = 5(12+n)

  • 5 months ago

    Mr. P is 76, and his granddaughter is 12. 

    x : y = 76 : 12 = 19 : 3

    (x + 4) : (y + 4) = 5 : 1

    Mr. P. will be 5 times as old as his granddaughter

    in another 4 years.

  • 5 months ago

    In n years, Mr. P will be (76+n) years old and his granddaughter will be (12+n) years old.  If at that time, he is five times as old as her, you can write that as:

        76 + n = 5(12 + n)

        76 + n = (5)(12) + 5n                   Use the distributive property a(b+c) = ab+ac

        76 + n = 60 + 5n                          Simplify

        16 + n = 5n                                  Subtract 60 from both sides

         16      = 4n                                  Subtract n from both sides

           4      =  n                                   Divide both sides by 4

    So, that will happen in 4 years.

  • 5 months ago

    76 + x = 5(12+ x)

    ==> 76 + x = 60 + 5x

    ==> 16 = 4x

    ==> x = 4

    So, in four years, he's be 5 times as old as his granddaughter

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