Reasoning – Data Sufficiency
What is Data Sufficiency?
These questions test whether the given data is adequate to answer a question, rather than solving the question itself.
Format of Questions
Each question has a question followed by two statements. You must determine whether the data provided in one or both statements is sufficient to answer the question.
Example Questions
- Question: What is the value of \(x\)?
Statement I: \(x + y = 10\)
Statement II: \(y = 4\)
Answer: Answer: Both I and II together are sufficient.
- Question: Is A older than B?
Statement I: A is older than C.
Statement II: C is older than B.
Answer: Answer: Both statements together are sufficient.
Exam Tips
- Do not solve the full question — only check sufficiency.
- Test each statement alone before combining.
- Look for unique determinability — can one and only one value/answer be obtained?
- Apply elimination: If one statement gives multiple outcomes, it's insufficient.
Common Mistakes
- Trying to find the exact answer instead of judging sufficiency.
- Combining statements before testing them individually.
- Ignoring indirect implications of a statement.
Quick Revision Checklist
- Use standard answer format options (I alone, II alone, Both together, Neither).
- Work on algebraic and logical sufficiency types.
- Ensure clarity on what constitutes 'sufficient'.
Summary: Data Sufficiency questions measure logical assessment of adequacy. Practice helps in resisting the urge to solve completely and focusing on what is needed to answer.