In this letter sequence odd one out question, choose the six letter group that does not end with three letters in strictly descending order among IJKRQP, FGHUTS, BCDWXY and KLMPON.

Introduction / Context:
This is a letter sequence odd one out question that focuses on patterns within six letter groups. Each group has three letters in the beginning and three letters at the end. The aim is to identify which sequence does not share the same pattern of the last three letters being in strictly descending alphabetical order.

Given Data / Assumptions:

• The letter groups are IJKRQP, FGHUTS, BCDWXY and KLMPON.
• We use standard alphabetical positions from A to Z.
• The pattern primarily concerns the order of the last three letters in each sequence.

Concept / Approach:
The idea is to separate each six letter group into the first three letters and the last three letters. On inspection, three of the groups end with three letters in descending order, while one group ends with three letters in ascending order. The group that does not follow the descending order pattern is the odd one out.

Step-by-Step Solution:
Step 1: For IJKRQP: the last three letters are R, Q and P. In the alphabet, R comes before Q and Q comes before P, so they are in descending order.Step 2: For FGHUTS: the last three letters are U, T and S. U comes before T and T comes before S, again forming a descending sequence.Step 3: For KLMPON: the last three letters are P, O and N. P comes before O and O comes before N, so they also form a descending sequence.Step 4: For BCDWXY: the last three letters are W, X and Y. Here, W comes before X and X comes before Y, which is an ascending sequence, not descending.Step 5: Since the last three letters in IJKRQP, FGHUTS and KLMPON are in descending order, while BCDWXY ends in ascending order, BCDWXY is the odd one out.
Verification / Alternative check:
You can double check by writing the last three letters of each group separately and comparing them: RQ P, U T S, P O N are backwards runs, whereas W X Y is a forward run in the alphabet. This direct comparison makes it clear that only BCDWXY does not share the pattern of descending order in the final trio of letters.

Why Other Options Are Wrong:
IJKRQP is not the odd one out because RQ P is in strict descending alphabetical order.
FGHUTS is not the odd one out since U T S is also a descending sequence.
KLMPON likewise ends with P O N, which again is in descending order, aligning it with the previous two.

Common Pitfalls:
Some candidates may focus on the first three letters instead of the last three or try to find more complicated patterns in the entire six letter sequence. While such patterns may exist, the simplest and most consistent feature here is the ordering of the last three letters. Always start with the most obvious and consistent pattern, especially when dealing with exam questions under time constraints.

Final Answer:
The only sequence whose last three letters are in ascending, not descending order, is BCDWXY, so BCDWXY is the odd one out.