Number And Alphabet Sequence - Number Set


Number Alphabet Sequence - Concepts
Class - Reasoning Proficiency For Employment Subjects
 
 
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 5's are there in the following number sequence, which are immediately preceded by 7 and immediately followed by 6?

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

    Right Option : A
    View Explanation
    Explanation
    Question : 2

    How many 7's are immediately preceded by 6 but not immediately followed by 5 in the following series of numbers?

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

    Right Option : D
    View Explanation
    Explanation
    Question : 3

    How many 9's are there in the following sequence, which are neither preceded by 6 nor immediately followed by 3?

    9 3 8 6 9 9 5 9 3 7 8 9 1 9 3 9 6 3 9

    Right Option : C
    View Explanation
    Explanation
     
     
     
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