ReasoningAbility.com

Find Wrong Term in Series

Find Wrong Term problems present an arithmetic progression where one term is incorrect. You must identify which term breaks the AP pattern and find the correct term.

10Worksheets
200+Practice Questions
IntermediateDifficulty
2-3 hoursHours to Master

What You'll Learn

Introduction & Overview Why This Matters How to Solve Pro Tips & Tricks
Shortcut Methods Common Mistakes Practice Worksheets Exam Importance

Introduction to Find Wrong Term in Series

Find Wrong Term problems present an arithmetic progression where one term is incorrect. You must identify which term breaks the AP pattern and find the correct term.

Prerequisites

Arithmetic Progression concepts Common difference identification Pattern recognition
Why This Matters: Find Wrong Term problems appear in 1-2 questions in SSC CGL and Banking PO exams. They test your ability to detect pattern breaks.

How to Solve Find Wrong Term in Series Problems

1

Step 1: List all given terms with their positions

2

Step 2: Calculate the common difference between consecutive terms

3

Step 3: Identify which difference does not match the pattern

4

Step 4: Determine the correct term by using the common difference from the valid part

5

Step 5: Verify that all terms follow the AP after correction

6

Step 6: Answer with the wrong term and/or its correct value

Pro Strategy: Calculate differences between consecutive terms. The common difference should be constant (or follow a pattern). The term that causes an irregularity is the wrong term.

Example Problem

Example: Find the wrong term: 3, 7, 11, 15, 19, 24, 27 Solution: Step 1: Differences: 7-3=4, 11-7=4, 15-11=4, 19-15=4, 24-19=5, 27-24=3 Step 2: Pattern is +4, but 24-19=5 (different) Step 3: Correct term after 19 should be 19+4=23 Step 4: Then 23+4=27 ✓ Step 5: Wrong term is 24, correct is 23 Answer: 24 is wrong; correct term is 23

Pro Tips & Tricks

  • Check differences between consecutive terms first
  • If differences vary, calculate differences of differences for higher-order patterns
  • The wrong term usually affects two differences (the one before and after it)
  • Sometimes the first or last term might be wrong
  • For longer sequences, compare differences from both ends
  • Verify by calculating the correct term and checking neighbors

Shortcut Methods to Solve Faster

If d is constant except at one point, that point's term is wrong
Correct term = (term_before + term_after)/2 if AP
Use two known good terms to find d, then check each term

Common Mistakes to Avoid

Assuming the first term is always correct
Not checking all differences systematically
Fixing the wrong term but not verifying neighbors
Overlooking that the common difference could be negative

Exam Importance

Find Wrong Term in Series is an important topic for various competitive exams. Here's how frequently it appears:

SSC CGL
1-2 questions
BANKING PO
1-2 questions
RAILWAYS RRB
1-2 questions
CAT
0-1 questions
INSURANCE
1-2 questions

Ready to Master Find Wrong Term in Series?

Start with Worksheet 1 and work your way up to expert level! Each worksheet includes:

20 practice questions
Detailed solutions
Step-by-step explanations
Start Practicing Now