Number series – find the wrong term (identify the outlier) Series: 8, 13, 21, 32, 47, 63, 83
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A13
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B21
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C32
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D47
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E83
Answer
Correct Answer: 47
Explanation
Introduction / Context:You need to identify the single erroneous term in a steadily increasing series. These questions often use simple, steadily growing increments; one term will break the rule.
Given Data / Assumptions:
- Series: 8, 13, 21, 32, 47, 63, 83.
- Exactly one term is incorrect.
Concept / Approach:Examine first differences. For many such sequences, the differences themselves increase with a constant step. If the step is consistent except at one place, that term is the outlier.
Step-by-Step Solution:
Compute differences: 13−8 = 5; 21−13 = 8; 32−21 = 11; 47−32 = 15; 63−47 = 16; 83−63 = 20.A natural pattern would be to increase the difference by +3 each time: 5, 8, 11, 14, 17, 20.Following this, after 32 the next increment should be 14 (not 15), giving 32 + 14 = 46.Therefore the term 47 is inconsistent; it should have been 46 for a perfect +3-difference ladder.Verification / Alternative check:With the corrected 46, the next differences continue +3: 46→63 is +17 and 63→83 is +20, matching the intended pattern 5, 8, 11, 14, 17, 20.
Why Other Options Are Wrong:
- 13, 21, 32, 83 are compatible with a steadily increasing difference sequence; removing any of them breaks more than one step and cannot restore a clean +3 progression.
Common Pitfalls:Assuming Fibonacci-like addition without checking differences; not verifying the entire tail after a suspected correction.
Final Answer:47