Number And Alphabet Sequence - Number Set


 
 
Concept Explanation
 

Number And Alphabet Sequence - Number Set

Number/alphabet sequence is a combination of numeric and/or alphabetic characters. Before starting with the questions, let us understand the meaning of 'following', 'followed by', 'preceding' and preceded by'. 

  • Take two consecutive letters A and B. Here, A is preceding B or B is preceded by A. Also, B is following A or and A is followed by B.
  • Now, take three consecutive letters A, B and C. Here, A and B are preceding C. However, B is immediately preceding C, whereas A is not immediately preceding C. Similarly, B and C are following A. However, B is immediately following A, whereas C is not immediately following A.
  • There are different types of questions in number/alphabet sequence
  • In this type of questions, generally a set, group or series of numerals is given and the candidate is asked to trace out numerals following certain given conditions of lying at specific mentioned positions after shuffling according to a certain given pattern.

    Example 1 : How many such 5s are there in the following number sequence each of which is immediately preceded by 3 or 4 but not immediately followed by 8 or 9 ?

    3 5 9 5 4 5 5 3 5 8 4 5 6 7 3 5 7 5 5 4 5 2 3 5 1 0

    (a) None             (b) Three              (c) Four               (d) Five            (e) None of these

    Solution : As you know, a number which comes after a given number is said to follow it while the one which comes before the given number precedes it. Thus, the numbers satisfying the given conditions may be marked as follows :

    3 5 9 5 4 5 5 3 5 8 4 5 6 7 3 5 7 5 5 4 5 2 3 5 1 0

    Clearly, there are five such 5s. Hence, the answer is (d).

    Example 2: In the series,  6 4 1 2 2 8 7 4 2 1 5 3 8 6 2 1 7 1 4 1 3 2 8 6. How many pairs of successive numbers have a difference of 2 each ?

    (a) Four             (b) Five               (c) Six               (d)  Seven

    Solution : Clearly, the pairs of successive numbers having a difference of 2 can be shown as follows :

    Thus, there are six such pairs. Hence, the answer is (c).

    Sample Questions
    (More Questions for each concept available in Login)
    Question : 1

    How many 7's immediately are preceded by 6 but not immediately followed by 4 are there in the following series?

    7 4 2 7 6 4 3 6 7 5 3 5 7 8 4 3 7 6 7 2 4 0 6 7 4 3 

    Right Option : B
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    Explanation
    Question : 2

    In the series given below, count the number of 9's, each of which is not immediately preceded by 5 but is immediately followed by either 2 or 3.

     1 9 2 6 5 9 3 8 3 9 3 2 5 9 2 9 3 4 8 2 6 9 8 

    Right Option : B
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    Explanation
    Question : 3

    Study the following number sequence given below and answer the question. 8, 9, 7, 6, 3, 4, 2, 8, 9, 7, 6, 4, 5, 9, 2, 9, 7.

    How many 9's are there which are preceded by even numbers ?

    Right Option : D
    View Explanation
    Explanation
     
     
     
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