Number series – find the wrong term (identify the outlier) Series: 105, 85, 60, 30, 0, -45, -90

Question

Solve this multiple-choice question and choose the correct option.

Accepted Answer

Introduction / Context:Descending sequences frequently subtract steadily increasing steps. Your task is to detect the single number that breaks an otherwise clean pattern of subtractions. Given Data / Assumptions: Series: 105, 85, 60, 30, 0, -45, -90. Exactly one term is wrong. Concept / Approach:Check the consecutive differences; if they should grow by a fixed amount (such as +5), you can spot the misfit where a different jump occurs. Step-by-Step Solution: 105 → 85: −2085 → 60: −25 (difference magnitude grew by 5)60 → 30: −30 (grew by 5 again)Following this pattern, the next should be −35, so 30 − 35 = −5, not 0.From −5 continuing the +5 growth: −5 − 40 = −45; then −45 − 45 = −90.Therefore “0” is the incorrect term; the correct value at that position should be −5. Verification / Alternative check:Rewritten series with the corrected term: 105, 85, 60, 30, −5, −45, −90 has differences −20, −25, −30, −35, −40, −45, a perfect arithmetic progression of differences. Why Other Options Are Wrong: 105, 60, −45, −90 can all be retained when the single faulty “0” is fixed; the difference ladder becomes consistently stepwise by 5. Common Pitfalls:Stopping after noticing two identical steps (−30, −30) and calling an earlier term wrong; always project the rule forward to confirm. Final Answer:0

Number series – find the wrong term (identify the outlier) Series: 105, 85, 60, 30, 0, -45, -90

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