CSAT (Paper II): previous-year questions
1280 real UPSC Prelims questions (2011–2026) with the official answer and a clear explanation. 400 of them came in the last five papers.
How often UPSC asks this
Questions per year, counted from the official papers.
Subtopics
Arrangements, ranking, ordering and puzzles
142 questions
Clocks and calendars
5 questions
Coding-decoding, series, patterns, cubes, dice and visual reasoning
110 questions
Communication, interpersonal skills and decision-making
10 questions
Counting, permutations, combinations and probability
1 questions
Directions, blood relations and Venn diagrams
60 questions
General English: grammar, vocabulary and comprehension
20 questions
General Hindi: grammar, vocabulary, dialects and comprehension
25 questions
Geometry and mensuration
26 questions
Number system and basic algebra (divisibility, HCF/LCM, remainders, digits, equations)
196 questions
Percentages, profit and loss, discount, simple and compound interest
47 questions
Ratio, proportion, averages, mixtures and alligation
47 questions
Syllogisms, statements and conclusions, assumptions and arguments
89 questions
Time and work; pipes and cisterns
2 questions
Time, speed and distance; trains, boats and streams; races
48 questions
Attempt the questions
Newest papers first. Tap an option; the answer and the reason appear instantly.
Read the passage
The paradox of choice is illustrated by the story of Buridan’s ass. Jean Buridan, the 14th century philosopher, wrote about free will and the inability to choose due to numerous choices and uncertainties. In the story, a donkey stands between two equally appealing stacks of hay. Unable to decide which to eat, it starves to death. Changes in technology and innovations such as smart phones and tablets only exacerbate our glut of choices. Constant connectivity and overconsumption of real-time data and social media can leave little room for self-reflection and rest, making decisions more difficult. Life is about choices. Many people are overwhelmed with attractive life choices, yet find themselves unhappy and anxious.
Which one of the following statements best reflects the most logical message implied by the above passage ?
Answer (d) & explanation
The message is that too few choices may be bad, but too many can be just as hard (d). Step 1: the passage tells of Buridan's ass, which starved between two equally good stacks of hay because it could not choose. Step 2: it says technology adds to our "glut of choices", leaving people unhappy and anxious, yet "life is about choices". That is the paradox of choice, so (d). Step 3: option (b) calls the choices difficult; the passage calls them attractive. Option (a) blames technology for weakening society. Option (c), lacking courage, is not discussed.
Tip: "paradox" signals two sides. Pick the option that holds both: choices are needed, but too many overwhelm.
Answer as per the official UPSC answer key.
What is the unit digit in the expansion of (57242)9×7×5×3×1 ?
Answer (a) & explanation
The unit digit is 2 (a). Step 1: only the last digit of 57242 matters, which is 2. Powers of 2 end in the cycle 2, 4, 8, 6, of length 4. Step 2: the power is 9 × 7 × 5 × 3 × 1 = 945. 945 ÷ 4 leaves a remainder of 1. Step 3: remainder 1 gives the first term of the cycle: 2. Options (b), (c) and (d) are other cycle terms.
Tip: an odd power can never be a multiple of 4. A product of odd numbers is always odd, which quickly rules out the 4th term (6).
Answer as per the official UPSC answer key.
Choose the group which is different from the others :
Answer (d) & explanation
Group (d) is the odd one out (d). Step 1: check whether each number is prime. Groups (a) 17, 37, 47, 97; (b) 31, 41, 53, 67; and (c) 71, 73, 79, 83 contain only primes. Step 2: in group (d), 91 = 7 × 13, which is not prime. Step 3: so (d) is different. Options (a), (b) and (c) all fit the pattern.
Tip: 91 looks prime but is 7 × 13. Other common traps are 51 (3 × 17), 57 (3 × 19) and 87 (3 × 29).
91 looks prime but is 7 × 13. Learn this one by heart.
Answer as per the official UPSC answer key.
Read the passage
“Science by itself is not enough, there must be a force and discipline outside the sciences to coordinate them and point to a goal. It is not possible to run a course aright when the goal itself has not been rightly placed. What science needs is philosophy — the analysis of scientific method and the coordination of scientific purposes and results; without this, any science must be superficial. Government suffers, precisely like science, for lack of philosophy. Philosophy bears to science the same relationship which statesmanship bears to politics : movement guided by total knowledge and perspective, as against aimless and individual seeking. Just as the pursuit of knowledge becomes scholasticism when divorced from the actual needs of men and life, so the pursuit of politics becomes a destructive bedlam when divorced from science and philosophy.”
Which one of the following statements best reflects the most rational, logical and practical message conveyed by the passage ?
Answer (b) & explanation
The message is that government should not be run only by practical statesmen, but with people of learning and wisdom (b). Step 1: the passage says science needs philosophy to give it a goal. Step 2: it says government suffers "like science, for lack of philosophy". Politics without science and philosophy becomes "destructive bedlam". So practical statesmen need learned, wise people alongside. That is (b). Step 3: options (a) and (c) prescribe training schemes the passage never proposes. Option (d), all scientists as philosophers, is too absolute.
Tip: this passage is from Will Durant on Plato. Pick the option that applies the passage's comparison (science-philosophy, politics-statesmanship) to government.
Answer as per the official UPSC answer key.
How many distinct 8-digit numbers can be formed by rearranging the digits of the number 11223344 such that odd digits occupy odd positions and even digits occupy even positions?
Answer (c) & explanation
1. The odd digits are 1, 1, 3, 3. They go into the 4 odd places. Two places get 1 and two get 3. Choosing which two places get the 1s can be done in 6 ways (list them: 12, 13, 14, 23, 24, 34).
2. The even digits 2, 2, 4, 4 go into the 4 even places in the same way: 6 ways.
3. Each choice on one side goes with each choice on the other: 6 × 6 = 36.
Answer as per the official UPSC answer key.
Read the passage
Sourcing food from non-agricultural lands (uncultivated systems such as forests, wetlands, pastures, etc) in addition to agricultural lands enables a systemic approach to food consumption. It allows rural and tribal communities to sustain themselves for the whole year and steer clear of natural disasters and season-induced shortfalls of agricultural food. Since the productivity of trees is often more resilient to adverse weather conditions than annual crops, forest foods often provide a safety net during periods of food shortages caused by crop failure; forest foods also make important contributions during seasonal crop production gaps.
Which one of the following statements best reflects the most logical and rational message conveyed by the author of the passage ?
Answer (d) & explanation
The message is that agroecosystems should be developed along with conventional agriculture (d). Step 1: the passage says sourcing food from forests, wetlands and pastures "in addition to agricultural lands" helps communities all year. Step 2: forest foods act as a safety net when crops fail. They supplement farming, not replace it. That is (d). Step 3: option (a) says food trees should replace other trees, and option (b) says conventional farming cannot ensure food security; both overreach. Option (c), converting wastelands, is not mentioned.
Tip: "in addition to" is the key phrase. Reject options that turn "addition" into "replacement".
Answer as per the official UPSC answer key.
ABCD is a square. One point on each of AB and CD; and two distinct points on each of BC and DA are chosen. How many distinct triangles can be drawn using any three points as vertices out of these six points?
Answer (c) & explanation
20 triangles can be drawn (c). Step 1: any 3 of the 6 points make a triangle, unless all 3 lie on one straight line. Step 2: the most points on any one side is 2. So no three chosen points are in a line. Step 3: the number of ways to choose 3 from 6 = (6 × 5 × 4) ÷ (3 × 2 × 1) = 20. Options (a), (b) and (d) wrongly subtract or add cases.
Tip: number of triangles = C(n, 3) minus the groups of 3 points that are in a line. Here there are none to subtract.
Answer as per the official UPSC answer key.
Read the passage
Household finance in India is unique. We have a tendency to invest heavily in physical assets such as gold and property. Steps to encourage the financialization of savings are critical. A populace accustomed to traditional processes will not simply jump into financialization. Hurdles to change include onerous bureaucracy, a scepticism of organized financial institutions, a lack of basic information about which of the myriad services and providers is best for each family, and how (and even if) one can make the transition between them if necessary.
Regarding the financialization of household savings, which of the following statements best reflect the solutions that are implied by the passage ?
- 1. A flexible environment is needed to develop solutions.
- 2. Households need customised solutions.
- 3. Innovations in financial technology are required.
Select the correct answer using the code given below :
Answer (d) & explanation
All three solutions are implied (d). Step 1: the passage lists hurdles to financialising savings. "Onerous bureaucracy" implies the need for a flexible environment (1). Step 2: the lack of information on which service is "best for each family" implies customised solutions (2). Step 3: the lack of information and the difficulty of moving between providers imply the need for fintech innovation (3). So options (a), (b) and (c) fail.
Tip: when a passage lists problems, each problem implies its own solution. Match them one by one. Indians traditionally save in gold and property, which this passage calls physical assets.
Answer as per the official UPSC answer key.
If ABC and DEF are both 3-digit numbers such that A, B, C, D, E and F are distinct non-zero digits such that ABC + DEF = 1111, then what is the value of A + B + C + D + E + F ?
Answer (d) & explanation
The sum of the six digits is 31 (d). Step 1: units place: C + F must end in 1. Two non-zero digits cannot add to 1, so C + F = 11, carrying 1. Step 2: tens place: B + E + 1 must end in 1, so B + E = 10, carrying 1. Step 3: hundreds place: A + D + 1 = 11, so A + D = 10. Total = 11 + 10 + 10 = 31. Options (a), (b) and (c) miss the carries.
Tip: in addition puzzles, work from the units place and track the carry at each step.
don't forget the carries. Without them you get 1 + 1 + 1 per column and land on a wrong option.
Answer as per the official UPSC answer key.
Read the passage
Scientists studied the vernal window — transition period from winter to the growing season. They found that warmer winters with less snow resulted in a longer lag time between spring events and a more protracted vernal window. This change in the spring timetable has ecological, social and economic consequences — for agriculture, fisheries and tourism. As the ice melts earlier, the birds don’t return, causing a delay, or lengthening in springtime ecological events.
With reference to the above passage, the following assumptions have been made :
- 1. Global warming is causing spring to come early and for longer durations.
- 2. Early spring and longer period of spring is not good for bird populations.
Which of the above assumptions is/are correct ?
Answer (a) & explanation
Only assumption 1 is correct (a). Step 1: the passage says warmer winters with less snow cause a "more protracted vernal window" and earlier ice melt. So global warming makes spring come early and last longer (1). Step 2: it says birds don't return on time, delaying spring events. Step 3: but it does not say bird populations suffer. Late return is not the same as harm to numbers. So assumption 2 fails, and options (b), (c) and (d) fail.
Tip: "vernal" means spring. A change in timing is not proof of a fall in numbers; don't stretch the passage.
Answer as per the official UPSC answer key.
Read the passage
“The last end of the state is not to dominate men, nor to restrain them by fear; rather it is so to free each man from fear that he may live and act with full security and without injury to himself or his neighbour. The end of the state, I repeat, is not to make rational beings into brute beasts and machines. It is to enable their bodies and their minds to function safely. It is to lead men to live by, and to exercise, a free reason; that they may not waste their strength in hatred, anger and guile, nor act unfairly toward one another.”
Based on the above passage, which one of the following terms best expresses the ultimate goal of the state ?
Answer (d) & explanation
The ultimate goal of the state is liberty (d). Step 1: the passage says the state's end is "not to dominate men" but to "free each man from fear". Step 2: it adds that the state should lead men to live by and use "a free reason". Freedom runs through every line. That is (d). Step 3: option (a), personal safety, and option (b), health of body and mind, are only parts of this freedom. Option (c), communal harmony, is a side effect at most.
Tip: this is Spinoza's view: "the end of the state is really liberty". Pick the term that sums up all the lines, not one detail.
Answer as per the official UPSC answer key.
A, B, C working independently can do a piece of work in 8, 16 and 12 days respectively. A alone works on Monday, B alone works on Tuesday, C alone works on Wednesday; A alone, again works on Thursday and so on.
Consider the following statements :
- 1. The work will be finished on Thursday.
- 2. The work will be finished in 10 days.
Which of the above statements is/are correct ?
Answer (a) & explanation
Only statement 1 is correct (a). Step 1: take total work = 48 units (LCM of 8, 16, 12). A does 6, B does 3 and C does 4 units a day. One 3-day cycle = 13 units. Step 2: three cycles (9 days) = 39 units. Day 10 (A) brings it to 45. Day 11 (B) brings it to 48. The work ends on day 11. Step 3: day 1 is Monday, so day 8 is Monday again and day 11 is a Thursday. Statement 1 is true; statement 2 (10 days) is false.
Tip: in rotating-work problems, use LCM units and count full cycles first, then finish day by day.
the last day is a B day, and B needs a full day for the last 3 units. So it takes 11 days, not 10.
Answer as per the official UPSC answer key.
Read the passage
While awareness on use/misuse and abuse of antibiotics is common knowledge, as is the impact of dosing poultry with antibiotics, the environmental impact of antibiotics-manufacturing companies not treating their waste has scarcely been discussed at any length or seriousness thus far. Pollution from antibiotics factories is fuelling the rise of drug-resistant infections. The occurrence of drug-resistant bacteria surrounding the pharma manufacturing plants is well known.
Which one of the following statements best reflects the most logical and practical message conveyed by the passage ?
Answer (a) & explanation
The practical message is that proper effluent treatment protocols are needed (a). Step 1: the passage says antibiotic factories "not treating their waste" is fuelling drug-resistant infections. Step 2: the direct fix for untreated waste is proper treatment protocols. That is (a). Step 3: option (b), awareness, is already "common knowledge" as the passage says. Option (c) calls the problem unavoidable, which the passage does not say. Option (d), moving plants to rural areas, only shifts the harm elsewhere.
Tip: the most practical solution attacks the exact cause named. Antimicrobial resistance (AMR) is a key global health threat; India runs a National Action Plan on AMR.
Answer as per the official UPSC answer key.
Read the passage
In India, the segregation of municipal waste at source is rare. Recycling is mostly with the informal sector. More than three-fourths of the municipal budget goes into collection and transportation, which leaves very little for processing/resource recovery and disposal. Where does waste-to-energy fit into all this ? Ideally it fits in the chain after segregation (between wet waste and the rest), collection, recycling, and before getting to the landfill. Which technology is most appropriate in converting waste to energy depends on what is in the waste (that is biodegradable versus non-biodegradable component) and its calorific value. The biodegradable component of India’s municipal solid waste is a little over 50 per cent, and biomethanation offers a major solution for processing this.
Based on the above passage, the following assumptions have been made :
- 1. Collection, processing and segregation of municipal waste should be with government agencies.
- 2. Resource recovery and recycling require technological inputs that can be best handled by private sector enterprises.
Which of the assumptions given above is/are correct ?
Answer (d) & explanation
Neither assumption is correct (d). Step 1: the passage describes the problems: little segregation, recycling mostly by the informal sector, and three-fourths of the budget spent on collection and transport. Step 2: it never says who should run collection and segregation, so assumption 1 (government agencies) has no basis. Step 3: it never compares public and private firms on recycling technology, so assumption 2 fails too. Options (a), (b) and (c) fail.
Tip: an assumption must be needed for the author's argument. If the passage never discusses who should do a job, any "who" assumption is out.
Answer as per the official UPSC answer key.
Read the passage
Pharmaceutical patents grant protection to the patentee for the duration of the patent term. The patentees enjoy the liberty to determine the prices of medicines, which is time-limited to the period of monopoly, but could be unaffordable to the public. Such patent protection offered to the patentees is believed to benefit the public over the longer term through innovations and research and development (R&D), although it comes at a cost, in the nature of higher prices for the patented medicine. The patent regime and price protection — through a legally validated high price for the medicine during the currency of the patent — provide the patentee with a legitimate mechanism to get returns on the costs incurred in innovation and research.
Based on the above passage, the following assumptions have been made :
- 1. Patent protection given to patentees puts a huge burden on public’s purchasing power in accessing patented medicines.
- 2. Dependence on other countries for pharmaceutical products is a huge burden for developing and poor countries.
- 3. Providing medicines to the public at affordable prices is a key goal during the public health policy design in many countries.
- 4. Governments need to find an appropriate balance between the rights of patentees and the requirements of the patients.
Which of the above assumptions are valid ?
Answer (b) & explanation
Assumptions 1 and 4 are valid (b). Step 1: the passage says patent prices "could be unaffordable to the public". So patents can burden people's buying power (1). Step 2: it also says patents reward R&D and benefit the public in the long run. So governments must balance patent rights and patients' needs (4). Step 3: assumption 2, dependence on imports, and assumption 3, other countries' policy goals, are outside the passage. So options (a), (c) and (d) fail.
Tip: India's Patents Act Section 3(d) blocks "evergreening" of patents, an example of balancing innovation with access to medicines.
Answer as per the official UPSC answer key.
D is a 3-digit number such that the ratio of the number to the sum of its digits is least. What is the difference between the digit at the hundred's place and the digit at the unit's place of D?
Answer (c) & explanation
The difference is 8 (c). Step 1: to make (number ÷ digit sum) small, keep the hundreds digit small and the other two digits large. Step 2: with hundreds digit 1, try the best options: 199 ÷ 19 ≈ 10.47; 189 ÷ 18 = 10.5; 198 ÷ 18 = 11. So 199 is best. With hundreds digit 2, the ratio is at least 299 ÷ 20 ≈ 15. Step 3: D = 199. The difference between hundreds and units digits = 9 − 1 = 8. Options (a), (b) and (d) fail.
Tip: the hundreds digit adds 100 per unit but only 1 to the digit sum. So keep it as small as possible.
Answer as per the official UPSC answer key.
Read the passage
A global analysis of nitrogen use efficiency — a measure of the amount of nitrogen a plant takes in to grow versus what is left behind as pollution — says that using too much fertilizers will lead to increased pollution of waterways and the air. Currently, the global average for nitrogen use efficiency is approximately 0·4, meaning 40 per cent of the total nitrogen added to cropland goes into the harvested crop while 60 per cent is lost to the environment, says a study. More than half of the world’s population is nourished by food grown with fertilizers containing synthetic nitrogen, which is needed to produce high crop yields. Plants take the nitrogen they need to grow, and the excess is left in the ground, water and air. This results in significant emissions of nitrous oxide, a potent greenhouse and ozone depleting gas, and other forms of nitrogen pollution, including eutrophication of lakes and rivers and contamination of river water.
Which one of the following statements best reflects the most logical, rational and crucial message implied by the passage ?
Answer (a) & explanation
The crucial message is that better nitrogen-use efficiency is needed for both food and the environment (a). Step 1: the passage says synthetic nitrogen feeds more than half the world's people. Step 2: but only 40% of it reaches the crop; 60% is lost as pollution, including nitrous oxide. So using nitrogen more efficiently serves both food and environment. That is (a). Step 3: option (b) covers only food. Option (c), alternative crops, is not raised. Option (d) discards fertilisers that the passage calls necessary for high yields.
Tip: nitrous oxide is both a greenhouse gas and ozone-depleting. India promotes neem-coated urea and Nano urea to cut nitrogen loss.
Answer as per the official UPSC answer key.
What is the remainder if 2192 is divided by 6 ?
Answer (d) & explanation
The remainder is 4 (d). Step 1: look at remainders of powers of 2 divided by 6: 2¹ = 2 → 2; 2² = 4 → 4; 2³ = 8 → 2; 2⁴ = 16 → 4. They alternate 2, 4, 2, 4. Step 2: odd powers leave 2 and even powers leave 4. Step 3: 192 is even, so the remainder is 4. Option (c), 2, is for odd powers. Options (a) and (b) are impossible, since a power of 2 is never a multiple of 3.
Tip: for remainders of large powers, list the first few. A short repeating cycle almost always appears.
Answer as per the official UPSC answer key.
Read the passage
To tackle the problem of pollution in cities, policy makers think that drastic actions like temporary use of odd-even number scheme for vehicles, closing schools, factories, construction activities, and banning the use of certain type of vehicles are a way forward. Even then the air is not clean. Vehicles more than 15 years old comprise one percent of the total; and taking them off the road will not make any difference. Banning certain fuels and car types arbitrarily is not proper. Diesel engines produce more PM 2·5 and less CO₂ than petrol or CNG engines. On the other hand, both diesel and CNG engines produce more NOₓ than petrol engines. No one has measured the amount of NOₓ that CNG engines are emitting. Arbitrary bans on vehicles that have passed mandated fitness tests and periodic pollution tests are unfair. What is needed is the scientific and reliable information about the source of pollutants on a continuing basis and the technologies that will work to reduce pollution from them.
Which one of the following statements best reflects the most logical and rational implication conveyed by the passage ?
Answer (b) & explanation
The implication is that knee-jerk reactions cannot fix pollution, but an evidence-based approach can (b). Step 1: the passage says drastic steps like odd-even and closing schools still leave the air unclean. Step 2: it ends: "What is needed is the scientific and reliable information about the source of pollutants". That is (b). Step 3: option (a) says curbs are difficult to implement; the passage calls them unfair, not hard. Option (c), heavy penalties, is not suggested. Option (d), lack of laws, is not discussed.
Tip: "unfair" and "difficult" are different complaints. Match the passage's exact objection.
Answer as per the official UPSC answer key.
Read the passage
Benefits of good quality school education accrue only when students complete and leave school after having acquired the gateway skills. Like one learns to walk before running, similarly one picks up advanced skills only after picking the basic foundational skills. The advent of the knowledge economy poses new challenges, and one of the severe consequences of having an uneducated workforce will be our inability to keep pace with the global economy. Without a strong learning foundation at the primary level, there can be no improvement in higher education or skill development.
Which one of the following statements best reflects the crux of the passage ?
Answer (a) & explanation
The crux is that to become a global power, India must invest in universal quality education (a). Step 1: the passage says advanced skills come only after foundational skills, as one walks before running. Step 2: an uneducated workforce would leave India unable to keep pace with the global economy. So universal quality schooling is the base. That is (a). Step 3: option (c) focuses on higher education, which reverses the passage's order. Option (b) says India is unable to become a power, which is too strong. Option (d), illiterate parents, is not mentioned.
Tip: India's NEP 2020 and NIPUN Bharat Mission stress foundational literacy and numeracy by Grade 3, the same idea as this passage.
Answer as per the official UPSC answer key.