Understanding and Completing the Letter Series

The question asks us to identify the pattern in the given letter series and find the term that completes it. The series is: CDZ, DGE, EJJ, FMO, GPT, ____.

To solve this type of letter series question, we typically look at the pattern of the letters in each position within the terms.

Analyzing the Pattern in Each Position

First Letter Analysis

Let's look at the first letter of each term:

• C
• D
• E
• F
• G

We can see a simple pattern here. The first letters are consecutive letters in the English alphabet. Following this sequence (C, D, E, F, G), the next letter should be H.

Second Letter Analysis

Now, let's examine the second letter of each term:

• D
• G
• J
• M
• P

Let's determine the position of each of these letters in the alphabet (A=1, B=2, ... Z=26):

• D is the 4th letter.
• G is the 7th letter.
• J is the 10th letter.
• M is the 13th letter.
• P is the 16th letter.

Let's find the difference between the positions of consecutive letters:

• G (7) - D (4) = 3
• J (10) - G (7) = 3
• M (13) - J (10) = 3
• P (16) - M (13) = 3

The pattern for the second letter is that each letter is 3 positions after the previous second letter in the alphabet. Following this pattern, the next second letter should be 3 positions after P (16th letter). The 16 + 3 = 19th letter is S.

Third Letter Analysis

Finally, let's look at the third letter of each term:

• Z
• E
• J
• O
• T

Let's determine the position of each of these letters in the alphabet (A=1, B=2, ... Z=26) and look for a pattern, considering wrapping around from Z back to A:

• Z is the 26th letter.
• E is the 5th letter. (From Z to E is a jump of $+5$ positions: Z $\to$ A $\to$ B $\to$ C $\to$ D $\to$ E)
• J is the 10th letter. (From E to J is a jump of $+5$ positions: 5 $\to$ 10)
• O is the 15th letter. (From J to O is a jump of $+5$ positions: 10 $\to$ 15)
• T is the 20th letter. (From O to T is a jump of $+5$ positions: 15 $\to$ 20)

The pattern for the third letter is that each letter is 5 positions after the previous third letter in the alphabet, wrapping around from Z to A. Following this pattern, the next third letter should be 5 positions after T (20th letter). The 20 + 5 = 25th letter is Y.

Combining the Patterns

Based on our analysis:

• The next first letter is H.
• The next second letter is S.
• The next third letter is Y.

Combining these letters, the next term in the series is HSY.

Verifying with Options

Let's check the given options:

1. HSY
2. HRZ
3. GRY
4. IQX

Our calculated next term, HSY, matches option 1.

Therefore, the option that fills in the blank and completes the given series is HSY.

Revision Table: Letter Series Patterns

Additional Information: Solving Letter Series Questions

Letter series questions are common in logical reasoning tests. They require identifying the rule or pattern that governs the sequence of letters or groups of letters. Here are some common types of patterns and strategies:

• Alphabetical Position: Look at the position of letters in the alphabet (A=1, B=2, etc.). The pattern might involve adding or subtracting a constant number, or a sequence of numbers ($+1, +2, +3, \dots$), to the letter positions.
• Consecutive Letters: Simple sequences like A, B, C or skipping letters like A, C, E.
• Skipping Letters: A pattern might involve skipping a fixed number of letters (e.g., jumping 2 letters every time: A $\to$ D $\to$ G).
• Reverse Alphabetical Order: The sequence might run backward (e.g., Z, Y, X).
• Combination of Patterns: Different positions within a term might follow different patterns, as seen in this question (first letter +1, second letter +3, third letter +5).
• Vowel/Consonant Patterns: The series might alternate between vowels and consonants or follow a pattern related to them.
• Symmetry or Reversal: Sometimes the series might be palindromic or involve reversing terms.

The best approach is often to analyze each position separately and note the changes. Converting letters to their numerical position in the alphabet can often reveal the underlying mathematical pattern more clearly.