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Discussion :: Number Series

  1. Consider the following series:
    A B C D .... X Y Z | Y X ...... B A | B C D ...... Y Z | Y X ..... C B A | B C ........ Y Z ....
    Which letter occupies the 1000th positing in the above series ?

  2. A.

     B

    B.

     C

    C.

     X

    D.

     Y

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    Answer : Option A

    Explanation :

    We have 3 patterns:
    I: A B C D ... X Y Z, which occurs only once.
    Y X ... B A, which repeats alternately.
    B C ... Y Z, which repeats alternately.
    Now, I: has 26 terms.
    So, number of terms before the desired term = (999 - 26) = 973.
    Each of the patterns which occurs after I: has 25 letters.
    Now, 973 ÷ 25 gives quotient = 38 and remainder = 23.
    Thus, the 1000th trem of the given series is the 24th term of the 39th pattern after I:.
    Clearly, the 39th pattern is II: and its 24th term is B.


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