Find the missing term in the sequence: 6, __, 21, 33, 48.
Aptitude
Odd Man Out and Series
Difficulty: Easy
Choose an option
-
A14
-
B20
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C12
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D18
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ENone of these
Answer
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:
- Sequence: 6, __, 21, 33, 48.
- Likely pattern: differences increasing by a constant.
Concept / Approach:
- Let the missing term be x. Differences: x−6, 21−x, 12, 15.
- If differences increase by 3 each time: (x−6), (21−x), 12, 15 with step +3.
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:
- 14, 18, 20: Break the constant +3 step in differences.
- None of these: Not applicable since 12 works perfectly.
Common Pitfalls:
- Guessing without checking later terms.
- Assuming constant difference instead of increasing difference.
Final Answer:12