Difficulty: Easy
Correct Answer: 12
Explanation:
Introduction / Context:We identify the pattern that generates this sequence. Many aptitude sequences use increasing differences with a fixed step. We infer the missing term consistently with later terms.
Given Data / Assumptions:
Concept / Approach:
Step-by-Step Solution:
Assume (21−x) − (x−6) = 3 ⇒ 21 − x − x + 6 = 3 ⇒ 27 − 2x = 32x = 24 ⇒ x = 12Check: Differences = 12−6 = 6, 21−12 = 9, 33−21 = 12, 48−33 = 15 (each +3)Verification / Alternative check:The +3 increase in differences is consistent across the entire sequence after inserting 12; pattern holds strictly.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:12
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