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

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:

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