The last four letters of the word CONCENTRATION are written in reverse order, followed by the next two letters in reverse order, then the next three letters in reverse order and finally the first four letters in reverse order. In this new arrangement, which letter is eighth from the right end?

Introduction / Context:
This question combines word manipulation with positional counting, both of which are common in reasoning exams. You are asked to rearrange segments of a word under specific rules and then determine the position of a letter from the right end. The word CONCENTRATION is used to construct a new sequence by reversing groups of letters in a particular order. Careful tracing of each step avoids confusion and leads to the correct final position.

Given Data / Assumptions:
The original word is CONCENTRATION, which has 13 letters. The instructions tell us to take the last four letters and write them in reverse order, then the next two letters (just before those four) in reverse, then the next three letters in reverse, and finally the first four letters in reverse. After performing all these operations, we obtain a new 13 letter arrangement. We are then asked to count from the right end and identify the letter that is eighth from that end.

Concept / Approach:
The key idea is to split the original word into segments according to the counts mentioned: last four, previous two, previous three and first four. We then reverse the letters inside each segment and concatenate these reversed blocks in the specified order. Once the new sequence is formed, counting from the right end becomes a straightforward indexing task. Breaking the problem into clear sub steps reduces the cognitive load and minimises errors.

Step-by-Step Solution:
Write CONCENTRATION with positions: C(1), O(2), N(3), C(4), E(5), N(6), T(7), R(8), A(9), T(10), I(11), O(12), N(13). Last four letters are T, I, O, N (positions 10 to 13). Reversing them gives N O I T. The next two letters before these four are R and A (positions 8 and 9). Reversing them gives A R. The next three letters before that are E, N and T (positions 5, 6 and 7). Reversing them gives T N E. The first four letters are C, O, N and C (positions 1 to 4). Reversing them gives C N O C. Putting the reversed blocks together in order we get the new arrangement: N O I T A R T N E C N O C.

Verification / Alternative check:
Now we count from the right end of the new sequence. From the right, the letters are: C (1st), O (2nd), N (3rd), C (4th), E (5th), N (6th), T (7th) and R (8th). Therefore the eighth letter from the right is R. As a cross check, you may also count from the left: N (1), O (2), I (3), T (4), A (5), R (6), T (7), N (8), E (9), C (10), N (11), O (12), C (13). From 13 letters, the eighth from the right corresponds to position 13 - 8 + 1 = 6 from the left, which is also R. Both methods agree, confirming the result.

Why Other Options Are Wrong:
E appears in the new arrangement but it is fifth from the right, not eighth. N appears multiple times but none of its occurrences is at the eighth position from the right. T and C occupy other positions when counted from the right and do not match the required eighth position. Only R consistently matches the count when we carefully trace and list all letters in their new order. Therefore any option other than R contradicts the explicit counting from the rearranged sequence.

Common Pitfalls:
Many learners misread the instruction and reverse the entire word instead of reversing the specified groups separately. Another common mistake is to take the wrong segments, for example choosing the last four correctly but then selecting the incorrect next two letters. Counting from the left instead of from the right as asked in the question also leads to the wrong answer. To avoid these pitfalls, underline the segments on the original word, reverse them one by one, and write the new sequence clearly on paper. Finally, be sure to count carefully from the correct end of the word.

Final Answer:
In the new arrangement of CONCENTRATION, the letter that is eighth from the right end is R.