Results 1 to 5 of 5

Math Help - safes and vault lock combinations qns

  1. #1
    Newbie
    Joined
    Jul 2008
    Posts
    8

    safes and vault lock combinations qns

    A safe and vault lock needs to be open.

    there are 100 numbers on the dial. ( 0~99 )

    The cue is the numbers are whole numbers. (includes zero)

    The 3 numbers must be in order to open up the lock
    ... eg , 40,60,90 not the same as 90 ,60 ,40

    Numbers may be repeat,
    eg : 20, 20, 80 or 20 80 20 or 20 20 20

    In total, how many possible sets of numbers are there ?

    Pls show maths workings, and thanks !

    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by thomasleong View Post
    A safe and vault lock needs to be open.

    there are 100 numbers on the dial. ( 0~99 )

    The cue is the numbers are whole numbers. (includes zero)

    The 3 numbers must be in order to open up the lock
    ... eg , 40,60,90 not the same as 90 ,60 ,40

    Numbers may be repeat,
    eg : 20, 20, 80 or 20 80 20 or 20 20 20

    In total, how many possible sets of numbers are there ?

    Pls show maths workings, and thanks !
    (100) \cdot (100) \cdot (100) = 100^3 and the reason should be clear from the answer ....
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jul 2008
    Posts
    8
    i dont understand ... why 100x100x100 ?

    If the numbers are in mutiple of 10s, then = 10x10x10 ?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by thomasleong View Post
    i dont understand ... why 100x100x100 ?

    If the numbers are in mutiple of 10s, then = 10x10x10 ?
    Where have you said in your question that the numbers are in multiples of 10's?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jul 2008
    Posts
    8
    sorry abt the 10s ... and thanks !

    so is 1000 possible combinations ...

    This is a true account of one of my friend's mother safes, she forgot her numbers but remember clearly that the numebrs are in 10s ...

    Guess she will have to try 1000 times before her safe would open
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. combination lock
    Posted in the Discrete Math Forum
    Replies: 11
    Last Post: August 28th 2014, 06:24 AM
  2. Total number of combinations for combination lock
    Posted in the Advanced Statistics Forum
    Replies: 6
    Last Post: December 26th 2011, 10:11 AM
  3. Number of Lock Combinations
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: October 14th 2009, 08:10 PM
  4. Lock Combos
    Posted in the Statistics Forum
    Replies: 7
    Last Post: May 28th 2009, 08:27 AM
  5. Combination Lock
    Posted in the Statistics Forum
    Replies: 1
    Last Post: October 1st 2007, 03:11 PM

Search Tags


/mathhelpforum @mathhelpforum