In the following number series, find the wrong term: 26, 20, 16, 11, 8, 6, 5.

Introduction / Context:
This question tests your understanding of number series where each term is generated from the previous one using a fixed pattern. Instead of extending the series, you are asked to identify the one term that does not follow the rule. Such questions are common in bank and SSC examinations because they test pattern recognition and careful comparison skills.

Given Data / Assumptions:

• The series is: 26, 20, 16, 11, 8, 6, 5.
• Exactly one term is incorrect and must be identified.
• The underlying rule is expected to be simple and consistent.

Concept / Approach:
For wrong term problems, the most reliable approach is to look at the differences between consecutive terms and see if these differences follow a recognizable pattern. Often we see arithmetic progressions, geometric progressions, or systematic changes in differences, such as adding or subtracting consecutive integers. The term that breaks this simple rule is the wrong one.

Step-by-Step Solution:
Step 1: Compute the differences between consecutive terms. 26 → 20: difference = 26 - 20 = 6. 20 → 16: difference = 20 - 16 = 4. 16 → 11: difference = 16 - 11 = 5. 11 → 8: difference = 11 - 8 = 3. 8 → 6: difference = 8 - 6 = 2. 6 → 5: difference = 6 - 5 = 1. Step 2: Collect these differences: 6, 4, 5, 3, 2, 1. Step 3: Observe that if the series was correct, the differences should ideally form a simple decreasing pattern such as 6, 5, 4, 3, 2, 1. Step 4: To obtain decreasing differences 6, 5, 4, 3, 2, 1 from the starting value 26, the sequence should be: 26, 20, 15, 11, 8, 6, 5. Step 5: Therefore the correct third term should be 15, not 16. Hence 16 is the inconsistent value.

Verification / Alternative check:
If we replace 16 with 15, the differences become: 26 - 20 = 6, 20 - 15 = 5, 15 - 11 = 4, 11 - 8 = 3, 8 - 6 = 2, 6 - 5 = 1. This gives a clean descending sequence of differences, which is a very natural and exam friendly pattern. This confirms that 16 is indeed the wrong term and 15 would be the expected correct term in that position.

Why Other Options Are Wrong:
26, 20, 11, 8, 6, and 5 all fit perfectly once the third term is corrected to 15 because the differences around them match the required descending pattern. None of these values disturb the simple 6, 5, 4, 3, 2, 1 difference structure, so they cannot be considered as the wrong term in the series.

Common Pitfalls:
A common mistake is to assume the first term is wrong simply because it is the largest, or to look for multiplicative patterns when additive differences are much more natural in this type of question. Another frequent error is to stop checking after one or two differences instead of examining the full set. Always compute all consecutive differences so that the hidden structure is clearly revealed before deciding which number is incorrect.

Final Answer:
The number that breaks the clean descending pattern of differences is 16, so 16 is the wrong term in the given series.