Quantitative Ability
What the section tests
Quantitative Ability in NIFT's GAT measures arithmetic fluency and interpretation under time pressure: percentages, ratios, averages, profit and loss, time–speed–distance, mensuration, and simple data handling. The maths is school-level; the difficulty is choosing the right base and avoiding needless calculation.
Core rules and concepts
- Percentage change: change = (new − old) / old × 100. Successive changes multiply: a 20% rise then a 10% fall gives 1.20 × 0.90 = 1.08, an 8% net rise.
- Profit, loss, discount: profit% is on cost price unless stated; discount% is on marked price. SP = CP × (1 + profit/100); after two discounts, SP = MP × (1 − d1)(1 − d2).
- Ratio and proportion: keep units consistent; scale all parts by the same factor.
- Averages: average = sum / count; weighted average uses each group's size.
- Speed: 1 km/h = 5/18 m/s; distance = speed × time.
- Mensuration: area of circle = πr²; circumference = 2πr; volume of cuboid = l × b × h.
Worked example
A shirt marked ₹2,400 receives successive discounts of 20% and 10%. Find the selling price. Reasoning: first discount = 2,400 × 0.80 = 1,920; second = 1,920 × 0.90 = ₹1,728. Equivalent discount = 1 − (0.80 × 0.90) = 28%, not 30%. The second discount applies to the reduced price, not the marked price.
Traps that cost marks
Adding successive percentages; applying discount to cost price; mixing marked price and selling price; forgetting unit conversions; over-calculating when ratios cancel; misreading 'except' or 'not'.