Finding the Different Letter Group

This question asks us to identify the letter group that is different from the other three. We are given four options: NTD, RTI, QSJ, and EGV. To solve this type of letter-group analogy problem, we usually look for a pattern based on the position of letters in the English alphabet or other relationships between the letters.

Analyzing the Letter Groups by Positional Value

Let's list the positional value of each letter in the alphabet (A=1, B=2, ..., Z=26) for each group:

• NTD: N is the 14th letter, T is the 20th letter, D is the 4th letter.
• RTI: R is the 18th letter, T is the 20th letter, I is the 9th letter.
• QSJ: Q is the 17th letter, S is the 19th letter, J is the 10th letter.
• EGV: E is the 5th letter, G is the 7th letter, V is the 22nd letter.

Let's look for a pattern based on the differences between the positional values of consecutive letters within each group.

Calculating Differences Between Letters

Let's calculate the difference between the positional value of the first and second letter in each group:

• NTD: Position of T minus Position of N = \(20 - 14 = 6\).
• RTI: Position of T minus Position of R = \(20 - 18 = 2\).
• QSJ: Position of S minus Position of Q = \(19 - 17 = 2\).
• EGV: Position of G minus Position of E = \(7 - 5 = 2\).

Let's organize this information in a table:

Identifying the Pattern and the Different Group

Observing the table, we can see a clear pattern in the difference between the first and second letters:

• For RTI, QSJ, and EGV, the second letter's position is exactly 2 more than the first letter's position.
• For NTD, the second letter's position is 6 more than the first letter's position.

This difference in the pattern of positional values between the first two letters identifies NTD as the letter group that is different from the other three.

We can also check the difference between the second and third letters, but the pattern between the first two letters is sufficient to find the different group. Let's quickly check the second differences:

• NTD: T(20) to D(4). Difference is \(4 - 20 = -16\) or \(4 + 26 - 20 = 10\) (cyclic).
• RTI: T(20) to I(9). Difference is \(9 - 20 = -11\) or \(9 + 26 - 20 = 15\) (cyclic).
• QSJ: S(19) to J(10). Difference is \(10 - 19 = -9\) or \(10 + 26 - 19 = 17\) (cyclic).
• EGV: G(7) to V(22). Difference is \(22 - 7 = 15\).

The differences between the second and third letters (\(-16\), \(-11\), \(-9\), \(15\)) don't show a consistent pattern across all four groups, emphasizing that the pattern lies in the difference between the first two letters.

Therefore, the letter group NTD is the different one because the positional difference between its first two letters (N and T) is +6, whereas in the other groups (RTI, QSJ, EGV), the difference between the first two letters is +2.

Revision Table: Letter Group Analysis

Additional Information on Letter Analogy Reasoning

Letter analogy questions test your ability to find relationships between letters or groups of letters. Common patterns include:

• Positional Differences: Adding or subtracting a fixed number to the position of a letter to get the next letter (as seen in this question).
• Skip Counting: Skipping a fixed number of letters in the alphabet.
• Vowels and Consonants: Patterns based on whether letters are vowels or consonants.
• Alphabet Series: Letters following a sequence like AB, BC, CD, etc.
• Sum or Product of Positions: The sum or product of positional values following a pattern.
• Mirror Images: Letters that are equidistant from the beginning and end of the alphabet (A and Z, B and Y, etc.).

When solving these questions, it's helpful to write down the alphabet and its positional values or visualize them. Systematically checking for simple patterns like positional differences is often a good starting point.