Data Sufficiency: Age-based Sufficiency

Concept Explanation

Age DS problems test whether present or past/future ages can be determined from ratios and time shifts.

Standard Answer Choices

• A — Statement I alone is sufficient; Statement II alone is not.
• B — Statement II alone is sufficient; Statement I alone is not.
• C — Both together are sufficient, neither alone.
• D — Either statement alone is sufficient.
• E — Neither alone nor together is sufficient.

Age DS Focus

Translate “n years ago/later” into equations. Age ratios change over time unless you fix the time gap.

DS Decision Flow

1. State exactly what must be determined (number, ratio, yes/no, or comparison).
2. Test Statement I alone—sufficient or insufficient?
3. Test Statement II alone—sufficient or insufficient?
4. If neither alone works, combine both statements.
5. Choose A–E based on sufficiency; never pick a value when data do not fix it uniquely.

Common Traps in Age Problems

• Applying the same ratio at different time points.
• Forgetting that age difference stays constant.
• Missing integer constraints for present ages.