Data Sufficiency: Algebraic Sufficiency

Concept Explanation

Algebra DS items test whether equations or inequalities yield a unique value for unknowns.

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.

Algebraic DS Focus

Count independent equations vs unknowns. Watch for quadratics giving two roots unless extra constraints apply.

Common Traps in Algebra Problems

• Assuming x² = 4 gives unique x (x = ±2).
• Treating dependent equations as independent.
• Ignoring domain restrictions (positive integers, etc.).