Find the odd group of letters from the following alternatives based on the step pattern of alphabetical positions.

Introduction / Context:
This question tests your skill in recognizing and comparing step patterns in sequences of letters. Many reasoning questions in competitive exams involve such alphabet based patterns, so becoming comfortable with them is highly beneficial.

Given Data / Assumptions:

• The letter groups given are: DGI, JMO, PRT, and TWY.
• You must select the group that does not follow the same step pattern as the others.
• Assume the standard mapping A = 1, B = 2, up to Z = 26.

Concept / Approach:
The idea is to examine the numerical positions of the letters in each group and then look at the differences between consecutive letters. If three groups exhibit a particular pattern, such as +3 then +2, and one group exhibits a different pattern, that different group is the odd one out.

Step-by-Step Solution:
Step 1: For DGI, the letters D, G, and I have positions 4, 7, and 9. From 4 to 7 is a jump of +3, and from 7 to 9 is a jump of +2. Step 2: For JMO, the letters J, M, and O have positions 10, 13, and 15. From 10 to 13 is +3 and from 13 to 15 is +2. So this group follows a +3, +2 pattern. Step 3: For TWY, the letters T, W, and Y have positions 20, 23, and 25. From 20 to 23 is +3, and from 23 to 25 is +2, once again showing the +3, +2 pattern. Step 4: For PRT, the letters P, R, and T have positions 16, 18, and 20. The difference from 16 to 18 is +2, and from 18 to 20 is +2, which forms a +2, +2 pattern, not +3, +2. Step 5: Since three groups follow a +3 then +2 sequence, while PRT follows +2 then +2, PRT is the odd group of letters.

Verification / Alternative check:
You can also visualize the letters on a number line of alphabet positions. Mark each triple and draw arrows showing the jumps. In DGI, JMO, and TWY, the arrows clearly have lengths corresponding to +3 and then +2. In PRT, both arrows are shorter and equal, clearly representing +2 and +2. This visualization confirms that PRT is structurally different from the others with respect to the step pattern.

Why Other Options Are Wrong:

• DGI: Follows the +3, +2 step pattern and so matches JMO and TWY.
• JMO: Also exhibits a +3, +2 step between its letters, so it is not odd.
• TWY: Again follows the +3, +2 pattern and belongs to the main group.

Common Pitfalls:
Some candidates may wrongly focus on the actual letters instead of the step sizes, or they may check only one difference instead of both. As a result, they might miss the pattern entirely. A disciplined approach that always converts to numerical positions and computes all differences helps avoid such mistakes and leads to reliable answers.

Final Answer:
PRT