Quantitative Aptitude
Quantitative Aptitude in EPFO SSA covers number system, arithmetic, percentages, ratio and proportion, averages, time-work-distance, simple and compound interest, mensuration and data interpretation. The paper rewards formula recall plus estimation.
Core rules
- Percentage change is always on the original base: change/original × 100.
- Successive percentage changes multiply factors: +20% then -10% gives 1.20 × 0.90 = 1.08, or +8%.
- Time and work: if A does 1/a work per day and B does 1/b, together they do 1/a + 1/b.
- Speed = distance/time; convert km/h to m/s by multiplying 5/18.
- Simple interest = P × R × T/100; compound interest = P[(1+R/100)^T - 1].
- Mensuration: area of circle = πr²; volume of cylinder = πr²h.
Worked example
A shopkeeper marks an item 40% above cost and gives 25% discount. Find profit%. Let cost = ₹100. Marked price = ₹140. Selling price = 140 × 0.75 = ₹105. Profit = ₹5 on ₹100, so profit = 5%. Reasoning: discount applies to marked price, not cost.
Traps
- Do not apply discount to cost price.
- In time-work, more workers reduce time; do not add times directly.
- CI exceeds SI after the first year; do not use the SI formula for multi-year CI.
- Check units in mensuration and DI (cm vs m, lakh vs crore).