Number series (find the wrong term): 19, 26, 33, 46, 59, 74, 91 Exactly one number does not match the series rule. Identify it and explain the rule you used.

Introduction / Context:
Many series increase by repeating increments in pairs. Spotting these paired differences quickly reveals the odd term. We will analyze consecutive differences and look for a “repeat-twice then step-up” structure.

Given Data / Assumptions:

• Series: 19, 26, 33, 46, 59, 74, 91
• Only one term is to be wrong.

Concept / Approach:
Compute differences: +7, +7, +13, +13, +15, +17. A common intended pattern is adding an odd number twice, then moving to the next odd number twice: +7, +7, +13, +13, +15, +15, …

Step-by-Step Solution:
19 → 26: +7 ✔26 → 33: +7 ✔33 → 46: +13 ✔46 → 59: +13 ✔59 → 74: +15 ✔Next should repeat +15, giving 74 + 15 = 89, but the series shows 91 ✖Thus, 91 is the single inconsistent term; it should have been 89.

Verification / Alternative check:
Replace the last term with 89; the differences become +7, +7, +13, +13, +15, +15, which is a neat paired-odd-increments pattern.

Why Other Options Are Wrong:

• 26, 33, 46, 59, 74: All fit the “repeat the same odd increment twice” structure.
• 91: Breaks the expected final +15 step; it adds +17 instead.

Common Pitfalls:
Assuming strictly increasing odd increments every step (+7, +9, +11, …). Here the odd increments repeat in pairs, a frequent twist in exam patterns.

Final Answer:
91