Find the incorrect term in the following number series. Series: 10, 26, 74, 218, 654, 1946, 5834

Difficulty: Easy

Correct Answer: 654

Explanation:


Introduction / Context:
Some sequences apply the same transformation each time. Here the intended rule is multiply by 3 and then subtract 4. Identifying the consistent rule reveals the single term that does not comply.


Given Data / Assumptions:

  • Series: 10, 26, 74, 218, 654, 1946, 5834
  • Hypothesis: next = (current * 3) − 4.


Concept / Approach:
Test the rule across each transition. The term produced by a failed transition identifies the anomaly.


Step-by-Step Solution:
10 * 3 − 4 = 30 − 4 = 26 ✓ 26 * 3 − 4 = 78 − 4 = 74 ✓ 74 * 3 − 4 = 222 − 4 = 218 ✓ 218 * 3 − 4 = 654 − 4 = 650 (but the series shows 654 ✗) Continuing correctly: 650 * 3 − 4 = 1950 − 4 = 1946 ✓; 1946 * 3 − 4 = 5838 − 4 = 5834 ✓.


Verification / Alternative check:
Replacing 654 with 650 makes the rule hold for all steps.


Why Other Options Are Wrong:
26, 74, 218 each exactly equals 3×previous − 4; they are consistent and thus correct.


Common Pitfalls:
Missing the constant subtraction after the multiplication.


Final Answer:
654

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