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Question

Study the following letter - sequence and answer the question.
S T P Q T S P T R P T S R P S T  P T R P T M P T S
How many 'T's are there in the above sequence which are immediately preceded by 'P' but not immediately followed by 'S'?

The correct answer is
3

Letter Sequence Pattern Identification

This solution explains how to analyze the provided letter sequence to count specific occurrences of the letter 'T' based on the letters immediately surrounding it.

Letter 'T' Pattern Conditions

The task is to find the number of times the letter 'T' appears in the sequence, satisfying two conditions simultaneously:

  • The letter immediately preceding 'T' must be 'P'.
  • The letter immediately following 'T' must NOT be 'S'.

Sequence Breakdown and Analysis

The given letter sequence is:

S T P Q T S P T R P T S R P S T P T R P T M P T S

To find the qualifying 'T's, we will examine each occurrence of 'T' within this sequence and check if it meets both the preceding and following letter conditions.

Final Count of Qualifying 'T's

Let's systematically check each 'T' in the sequence:

Index Character Preceded By Followed By Preceded by 'P'? Followed by 'S'? Meets Criteria?
1 T S P No No No
4 T Q S No Yes No
7 T P R Yes No Yes
10 T P S Yes Yes No
13 T R P No No No
15 T S P No No No
17 T P R Yes No Yes
20 T P M Yes No Yes
23 T P S Yes Yes No

By carefully examining the sequence and applying the given conditions:

  • The 'T' at index 7 (part of the subsequence 'P T R') meets the criteria.
  • The 'T' at index 17 (part of the subsequence 'P T R') meets the criteria.
  • The 'T' at index 20 (part of the subsequence 'P T M') meets the criteria.

The other occurrences of 'T' do not meet the conditions. Therefore, there are exactly 3 'T's in the sequence that are immediately preceded by 'P' but not immediately followed by 'S'.

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Important Questions from Letter based

  1. Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the letter-cluster that is different.

  2. Three of the following four letter-clusters are alike in a certain way and one is different. Pick the odd one out.

  3. Four letter-clusters have been given, out of which three are alike in some manner, while one is different. Select the odd letter-cluster.

  4. Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the one that is different.

  5. Four letter-clusters have been given, out of which three are alike in some manner and one is different. Select the letter-cluster that is different.

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