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Math Help - Counting and Pattering G9 Help

  1. #1
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    Counting and Pattering G9 Help

    The digits 1,2, ,3 ,4 can be arranged to form twenty-four different four-digit numbers. If these twenty-four numbers are then listed from the smallest to largest, in what position is 3142
    Last edited by Frankasd; October 23rd 2008 at 06:02 PM.
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  2. #2
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    Smaller than 3142 are all numbers starting with "1" and "2". Than, the only number starting with 3 smaller that the one given is 3124. So, all in all, you have 6+6+1 numbers on the list that are smaller than 3142. (This means that 3142 is 14th number on the list).

    Anyway, I hope that You've already managed to solve it!

    best regards
    katastrofa.nadfioletu
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  3. #3
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    Hello, Frankasd!

    The digits 1,2,3,4 can be arranged to form 24 different 4-digit numbers.
    If these 24 numbers are then listed from the smallest to largest, in what position is 3142?

    The very least you could do is crank out the 24 numbers:

    . . \begin{array}{cc}(1)&1234\\(2)&1243\\(3)&1324\\(4)  &1342\\(5)&1423\\(6)&1432 \end{array} . . . . \begin{array}{cc}(7)&2134\\(8)&2143\\(9)&2314\\(10  )&2341\\(11)&2413\\(12)&2431\end{array} . . . . \begin{array}{cc}(13)&3124\\{\color{blue}(14)}&{\c  olor{blue}3142}\\(15)&3214 \\(16)&3241\\(17)&3412\\(18)&3421 \end{array} . . . . \begin{array}{cc}(19)&4123\\(20)&4132\\(21)&4213\\  (22)&4231\\(23)&4312\\(24)&4321 \end{array}

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