Quantitative Aptitude – UPSC CSAT

CSAT numeracy is pitched at Class X level, but the questions reward speed: knowing divisibility rules, remainders and unit-digit cycles lets you answer in seconds what would otherwise need long multiplication. Number-system ideas also sit…

HCF and LCM questions are quick marks in CSAT. They also appear disguised: bells ringing together, traffic lights, tiles that fit a floor, or the largest container that measures several quantities exactly. Recognising which of…

Percentages are the language of CSAT arithmetic: profit, interest, data interpretation and growth questions all reduce to them. Fluency with fraction equivalents and the successive-change formula saves minutes across the paper. Change % = (new…

Ratio questions test whether you can think in 'parts'. Once quantities are written as multiples of one unknown part, sharing money, mixing, ages and coins all become one-line problems. A : B = 3 :…

Average questions are among the fastest in CSAT if you work with totals and deviations instead of long sums. They also feed directly into data interpretation. Average = sum ÷ count, so sum = average…

Profit and loss questions are percentage questions with a business story. The single most important rule: profit and loss percentages are on cost price, discounts are on marked price. Take CP = 100. A 25%…

Interest questions in CSAT are short and formula-driven. Knowing a few relationships – especially the 2-year difference between compound and simple interest – turns them into mental arithmetic. Interest is earned only on the principal:…

Time-and-work questions look varied but share one structure: work = rate × time. The LCM (total units) method avoids fractions and is the fastest approach under exam pressure. Take the total work as the LCM…

Speed questions – trains, boats, races and journeys – are a CSAT staple. Most become one-line calculations once you fix units and identify the relative speed. km/h to m/s: multiply by 5/18; m/s to km/h:…

Mixture problems – blending grades of rice, diluting milk, combining acid solutions – are weighted averages in disguise. The alligation rule turns them into a two-step subtraction. When two ingredients at prices (or concentrations) c…

Counting questions appear every year in CSAT, often in simple settings: arranging people, forming numbers, choosing teams. The key decision is whether order matters. If one task can be done in m ways and a…

CSAT probability uses coins, dice, cards and balls. Every question is the ratio favourable ÷ total, provided the outcomes are equally likely – so careful counting is everything. P(event) = number of favourable outcomes ÷…

CSAT geometry stays at school level: angles, triangles, circles, areas and volumes. The marks come from remembering formulas exactly and spotting Pythagorean triples. Angles on a straight line add to 180°; around a point to…

CSAT algebra is light: forming and solving linear equations, simple quadratics, age problems and identities. The real skill is translating words into equations correctly. Translate carefully: 'x is 5 more than twice y' → x…