Number Series — Find the Wrong Term (Add 1110 Each Step) Which number is incorrect in: 1236, 2346, 3456, 4566, 5686?
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A1236
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B3456
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C4566
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D5686
Answer
Correct Answer: 5686
Explanation
Introduction / Context:Some sequences add a fixed constant each step. Spotting a neat addition such as +1110 quickly reveals the outlier that fails to follow the rule.
Given Data / Assumptions:
- Numbers: 1236, 2346, 3456, 4566, 5686
- Assume a single wrong term.
- Test for constant addition.
Concept / Approach:Check whether each term equals the previous plus 1110. This pattern aligns with the visible digit structures and is easy to validate by subtraction.
Step-by-Step Solution:2346 − 1236 = 1110 ✔3456 − 2346 = 1110 ✔4566 − 3456 = 1110 ✔5686 − 4566 = 1120 ✖ (should be 1110)Hence, the last value should be 4566 + 1110 = 5676, not 5686.
Verification / Alternative check:Replacing 5686 with 5676 yields a perfect constant increment sequence. Therefore 5686 is the incorrect term.
Why Other Options Are Wrong:
- 1236, 3456, 4566: Each maintains the +1110 progression; they are consistent and correct.
Common Pitfalls:Overcomplicating with multiplicative rules. Always try simple constant addition or subtraction first when digits suggest a steady shift.
Final Answer:5686