Quantitative Aptitude / Numerical Ability
Quantitative Aptitude / Numerical Ability
This section tests numerical fluency across simplification/approximation, number series, quadratic equations, arithmetic and data interpretation. Indian Bank LBO-level questions are usually moderate, so accuracy and choosing the short method matter more than long division.
Core rules
- Simplification: Use BODMAS and approximate only when options are far apart. Convert percentages to fractions (12.5% = 1/8, 16.66% = 1/6).
- Number series: Check differences, then ratios, then squares/cubes, then alternating or mixed patterns. Do not force one pattern beyond two steps.
- Arithmetic: For profit/loss, keep cost price as 100. For successive percentage changes, use net change = a + b + ab/100. For SI, I = PRT/100; for CI, A = P(1 + r/100)^t.
- Data interpretation: Read units and years first; calculate only what the question asks.
Worked example
A shopkeeper marks an article 40% above cost and allows a 25% discount. Find profit percent.
Let CP = 100. MP = 140. SP = 140 × (1 − 0.25) = 105. Profit = 105 − 100 = 5, so profit% = 5/100 × 100 = 5%. A common wrong method is 40% − 25% = 15%; discount is on MP, not CP, so percentages cannot be added directly.
Traps
- Applying discount to CP instead of MP.
- Using the SI formula for CI.
- Rounding too early in approximation.
- Missing 'per annum' vs 'per month' in interest.
- In DI, comparing absolute values when the question asks for percentage share.