School-Safe Puzzle Games

John, James, and Harry: a math brain teaser

math-allowance-brain-teaser

John, James, and Harry have $4.80 which they wish to divide equally among them. To do this, John, who has the most, gives to James and Harry as much as they already have. Then, James divides by giving John and Harry as much as they have after John’s division. Harry then divides with John and James in the same way, and it is found that they have equal sums.

How much had each at first?

As always, if you can figure this out, you may enter your answer in the ‘comment’ section below. Will reveal answers later on this week!

17 Comments to “John, James, and Harry: a math brain teaser”


  1. mimi112 | Profile

    John had $2.60, James had $1.40 and Harry had $0.80.


  2. fuzzy | Profile

    John had $2.60, James had $1.40, and Harry had 80 cents.
    After 1st division John was left with 40 cents, James had $2.80 and Harry had $1.60.
    After 2nd division James and John both had 80 cents each, and Harry had $3.20. Finally, after the 3rd division they each had $1.60.


  3. TheMadEgyptian | Profile

    Working backwards:
    John James Harry
    $1.60 $1.60 $1.60 Harry splits
    $ .80 $ .80 $3.20 James splits
    $ .40 $2.80 $1.60 John splits


    $2.60 $1.40 $ .80 Beginning


  4. tad | Profile

    John = 2.60
    James = 1.40
    Harry = 0.80


    This one is easiest worked out in reverse.


  5. hex | PUZZLE MASTER | Profile

    Assuming that “gives to James and Harry as much as they already have” implies he gives James as much as James has, and Harry as much as Harry has (not the sum of James and Harry divided by 2),
    John has $2.60
    James has $1.40
    Harry has $0.80


  6. Mashplum | PUZZLE MASTER | Profile

    John = $2.60
    James = $1.40
    Harry = $0.80


    Easy if you work backwards.


  7. michaelc | Profile

    John had $2.60.
    James had $1.40.
    Harry had $0.80.


    Then they all had a $1.60.


    So which one of the guys is John? :)


  8. Shawn | PUZZLE GRANDMASTER | Profile

    Hey, I can log-in again!!!


    John: $2.60
    James: $1.40
    Harry: $0.80


  9. bizarette18 | PUZZLE MASTER | Profile

    $2.60, $1.40, $0.80


  10. Hendy | Profile

    John James Harry
    rnd 1 $2.60 $1.40 $0.80
    rnd 2 $0.40 $2.80 $1.60
    rnd 3 $0.80 $0.80 $3.20
    rnd 4 $1.60 $1.60 $1.60


  11. rachel | Profile

    john starts with $2.60, james with $1.40 and Harry with .80c
    then john gives james $1.40 and harry .80c
    so..
    john: .40c james: $2.80 harry: $1.60
    then james gives john .40c and harry $1.60
    john: .80c james: .80c harry: $3.20
    then harry gives john .80c and james .80c
    john: $1.60 james: $1.60 harry: $1.60
    so they are all left with $1.60 each..


  12. APEX.JP | Profile

    John 260
    James 140
    Harry 80


  13. RK | Founder | Profile

    very good, answers above are correct!


  14. pravinkumar1942@gmail.com | Profile

    answer is


    John had $2.60,James had $1.40 and harry had $0.80 at the start.


  15. makada | Profile

    I really enjoyed solving this. Reminded me of my days in school.
    Below I post the way I solved it
    Initial money with john = x
    Initial money with james = y
    Initial money with henry = z


    x + y+z = 480


    x>y
    x>z
    After John’s division, each has the following amount
    x-y-z, 2y , 2z


    After James’ division, each has the following amount
    2(x-y-z),2y-2z-(x-y-z),4z


    After Henry’s division, each has the following amount
    4(x-y-z),4y-4z-2(x-y-z),4z-[2(x-y-z)+2y-2z-(x-y-z)]


    As they now have equal amounts then


    4(x-y-z) = 160
    4x-4y-4z=160
    x-y-z=40……..(1)
    x=40+y+z………(1a)


    4y-4z-2(x-y-z) = 160
    4y-4z-2x+2y+2z=160
    6y-2x-2z=160
    3y-x-z=80……..(2)
    Substituting for x from Eq 1a into Eq 2
    3y-40-y-z-z=80
    3y-40-y-2z=80
    2y-2z=120
    y-z=60
    y=60+z …..(3)
    Substituting y in Eq 1a
    x=40+60+z+z
    x=100+2z…….(4)


    4z-[2(x-y-z)+2y-2z-(x-y-z)]=160
    4z-[2x-2y-2z+2y-2z-x+y+z]=160
    4z-2x+2y+2z-2y+2z+x-y-z=160
    7z-x-y=160………(5)
    7z-100-2z-60-z=160
    4z-160=160
    4z=320
    z=320/4=80………….(ans)


    y=60+80=140….(ans)


    x=100+2*80=100+160=260……ans


  16. RK | Founder | Profile

    good job makada, it was a difficult problem :)


  17. makada | Profile

    My math teacher in school always used to tell me that I would some how find the most longest and cumbersome way to solve any problem…but he always said that as long as the answer is right, he will not stop my ‘creative’ thinking!!!
    ;-)


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