Results 1 to 3 of 3

Math Help - Master Lock Combination

  1. #1
    Newbie
    Joined
    Oct 2008
    Posts
    1

    Wink Master Lock Combination

    Ok, I have this lock and can't remember the combination. It's the standard Master Lock with 3 numbers in the combination and the numbers are 0 - 39. However, I do remember all three of the numbers are either 10,15,20,25,30, or 35. And none of the numbers are repeated. Can anyone think of good way to go about going through all the possibilities?

    PS - Thanks for reading and I've already tried the stuff about finding the 12 "sticks."
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Rhymes with Orange Chris L T521's Avatar
    Joined
    May 2008
    From
    Santa Cruz, CA
    Posts
    2,844
    Thanks
    3
    Quote Originally Posted by cowmoonrock View Post
    Ok, I have this lock and can't remember the combination. It's the standard Master Lock with 3 numbers in the combination and the numbers are 0 - 39. However, I do remember all three of the numbers are either 10,15,20,25,30, or 35. And none of the numbers are repeated. Can anyone think of good way to go about going through all the possibilities?

    PS - Thanks for reading and I've already tried the stuff about finding the 12 "sticks."
    I don't know if there is a good way to approach this...for there are 720 different combinations!

    --Chris
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,657
    Thanks
    598
    Hello, cowmoonrock!

    I have this lock and can't remember the combination.
    It has 3 numbers in the combination and the numbers are 0 - 39.
    However, I do remember all three of the numbers are either 10,15,20,25,30, or 35.
    And none of the numbers are repeated.
    Can anyone think of good way to go about going through all the possibilities?
    There are: . 6\cdot5\cdot4 \:=\:120 possible choices.


    To crank through all the combinations . . . call the six numbers: a,b,c,d,e,f



    Use the first two: . a\,b\,\_
    For the third, cycle through the other four numbers: . \begin{array}{c}ab{\color{blue}c} \\ ab{\color{blue}d} \\ ab{\color{blue}e} \\ ab{\color{blue}f}\end{array}

    Change the second number: . a\,c\,\_
    For the third, cycle through the other four numbers: . \begin{array}{c}ac{\color{blue}b} \\ ac{\color{blue}d} \\ ac{\color{blue}e} \\ ac{\color{blue}f} \end{array}

    Similarly, we have: . \begin{array}{c}adb\\adc\\ade\\adf\end{array} \quad \begin{array}{c}aeb \\aec \\ aed \\ aef \end{array}\quad \begin{array}{c}afb \\ afc \\ afd \\ afe \end{array}

    And we have the 20 that begin with a.



    To find the 20 that begin with b . . .

    Begin with: . b\,a\,\_
    Cycle through the other four numbers: . \begin{array}{c}ba{\color{blue}c} \\ ba{\color{blue}d} \\ ba{\color{blue}e} \\ ba{\color{blue}f} \end{array}
    Then: . \begin{array}{c}bca\\bcd\\bce\\bcf\end{array} \quad\begin{array}{c}bda\\bdc\\bde\\bdf \end{array}\quad\begin{array}{c}bea\\bec\\bed\\bef  \end{array}\quad\begin{array}{c}bfa\\bfc\\bfd\\bfe \end{array}


    And so on . . .

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Total number of combinations for combination lock
    Posted in the Advanced Statistics Forum
    Replies: 6
    Last Post: December 26th 2011, 10:11 AM
  2. 9-Digit Combination Lock Chances And Probability
    Posted in the Statistics Forum
    Replies: 9
    Last Post: June 25th 2011, 03:39 PM
  3. combination lock
    Posted in the Discrete Math Forum
    Replies: 10
    Last Post: April 19th 2010, 07:26 AM
  4. combination lock (question)
    Posted in the Statistics Forum
    Replies: 7
    Last Post: May 18th 2009, 04:08 PM
  5. Combination Lock
    Posted in the Statistics Forum
    Replies: 1
    Last Post: October 1st 2007, 03:11 PM

Search Tags


/mathhelpforum @mathhelpforum