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
Can a democracy avoid being a welfare state for long ? Why cannot mass welfare be left entirely to the markets ? There is a built-in tension between markets and democracy. Markets do not work on a one-person-one-vote principle as democracies do. What one gets out of the market place depends on one’s endowments, skills, purchasing power and the forces of demand and supply. Markets reward individual initiative and skill, and may also lift many from the bottom rungs of society, but some people never get the opportunity to develop skills that markets demand; they are simply too poor and too handicapped; or skill formation takes too long. By creating jobs, markets may be able to help even unskilled people, but capitalism has always witnessed bursts of unemployment.
With reference to the above passage, the following assumptions have been made :
- 1. Modern democracies rely on the market forces to enable them to be welfare states.
- 2. Markets ensure sufficient economic growth necessary for democracies to be effective.
- 3. Government programmes are needed for those left behind in economic growth.
Which of the above assumptions is/are valid ?
Answer (b) & explanation
Only assumption 3 is valid (b). Step 1: the passage asks why welfare cannot be "left entirely to the markets". It says some people never get to build the skills markets reward, and capitalism sees bursts of unemployment. So government programmes are needed for those left behind (3). Step 2: assumption 1 says democracies rely on markets to be welfare states. The passage says the opposite. Step 3: assumption 2 says markets ensure enough growth for democracy. The passage only says markets may lift some people. So options (a), (c) and (d) fail.
Tip: the tension between markets and democracy is a key idea. Markets work on "one rupee, one vote"; democracy works on "one person, one vote".
Answer as per the official UPSC answer key.
A biology class at high school predicted that a local population of animals will double in size every 12 years. The population at the beginning of the year 2021 was estimated to be 50 animals. If P represents the population after n years, then which one of the following equations represents the model of the class for the population ?
Answer (d) & explanation
The model is P = 50(2)^(n/12) (d). Step 1: doubling means multiplying, not adding. So the linear options (a) and (b) are out. Step 2: after 12 years, there should be exactly one doubling. Put n = 12: 2^(12/12) = 2¹ = 2, so P = 100. Correct. Step 3: option (c), 2^(12n), at n = 12 gives 2¹⁴⁴, which is absurdly large. So only (d) fits. After 24 years, (d) gives 50 × 4 = 200, again correct.
Tip: for growth that doubles every T years, use P = P₀ × 2^(n/T). Test an easy value of n to check any formula quickly.
Answer as per the official UPSC answer key.
In the English alphabet, the first 4 letters are written in opposite order; and the next 4 letters are written in opposite order and so on; and at the end Y and Z are interchanged. Which will be the fourth letter to the right of the 13th letter ?
Answer (b) & explanation
The letter is T (b). Step 1: reverse the alphabet in blocks of four: DCBA HGFE LKJI PONM TSRQ XWVU. Then Y and Z swap, giving ZY at the end. Step 2: count to the 13th letter. The first three blocks have 12 letters, so the 13th is the first letter of the 4th block: P. Step 3: the fourth letter to the right of the 13th is the 17th letter. That is the first letter of the 5th block: T. Option (a), N, comes from the normal alphabet. Options (c) and (d) are other miscounts.
Tip: write out the new order fully before counting. "Fourth to the right of the 13th" simply means position 13 + 4 = 17.
Answer as per the official UPSC answer key.
Read the passage
“...... most people would agree that telling deliberate lies is wrong, except perhaps in certain special situations where more harm will be done by telling the truth. Even the most truthful people probably tell a good many more lies that might be regarded as semantic lies; their use of words contains some measure of falsehood, more or less deliberate.”
The idea which the first part of the passage mentions is
Answer (d) & explanation
UPSC's key gives (d): disagreement about the harm in telling the truth. Step 1: the first part says most people agree deliberate lies are wrong, "except perhaps in certain special situations where more harm will be done by telling the truth". Step 2: UPSC reads the key idea as this exception: people differ on when telling the truth does harm. That is (d). Step 3: option (a), agreement about telling lies, also looks close because of "most people would agree". But UPSC picked the exception as the idea. Options (b) and (c) do not match the wording.
Tip: in short quotes, UPSC often tests the qualifier ("except", "unless"). The exception usually carries the idea being examined.
Answer as per the official UPSC answer key.
Integers are listed from 700 to 1000. In how many integers is the sum of the digits 10 ?
Answer (d) & explanation
9 integers have a digit sum of 10 (d). Step 1: numbers from 700 to 799 are written 7ab. We need a + b = 3: 703, 712, 721, 730. That is 4. Step 2: 8ab needs a + b = 2: 802, 811, 820. That is 3. 9ab needs a + b = 1: 901, 910. That is 2. Step 3: 1000 has digit sum 1, so it does not count. Total = 4 + 3 + 2 = 9. Options (a), (b) and (c) miss some.
Tip: two digits adding to k (with k ≤ 9) can be arranged in k + 1 ways. So 3 gives 4, 2 gives 3, 1 gives 2.
Answer as per the official UPSC answer key.
Read the passage
The best universities like Harvard and MIT, despite having the luxury of having some truly excellent teachers on their payroll, are increasingly embracing the “flipped classroom” format, where students listen to video lectures at home, and spend class time applying their knowledge, solving problems, discussing examples, etc. Professors guide that discussion and fill in wherever necessary, explaining those bits that seem to be eluding the students and throwing in advanced ideas that happen to be topical. These universities have made their video lectures available free for anyone in the world. They are also encouraging colleges and universities all over the world to integrate these online courses into their own pedagogy, picking the pieces that are appropriate for their needs and building a package around them.
Which one of the following statements best reflects the central idea of the passage given above ?
Answer (b) & explanation
The central idea is that higher education can be made easier to access and cheaper without diluting content (b). Step 1: top universities like Harvard and MIT put their video lectures online free for anyone. Other colleges can build these into their teaching. So good content reaches more people at low cost. That is (b). Step 2: option (a) says online mode is better than classroom. But the flipped classroom mixes both: videos at home, discussion in class. Step 3: option (c), no need for infrastructure, and option (d), coaching institutes thriving, are not in the passage.
Tip: a "flipped classroom" means lectures at home and problem-solving in class. Don't confuse blended learning with fully online learning.
Answer as per the official UPSC answer key.
A student appeared in 6 papers. The maximum marks are the same for each paper. His marks in these papers are in the proportion of 5 : 6 : 7 : 8 : 9 : 10. Overall he scored 60%. In how many number of papers did he score less than 60% of the maximum marks ?
Answer (b) & explanation
He scored below 60% in 3 papers (b). Step 1: the marks are in the ratio 5 : 6 : 7 : 8 : 9 : 10. Their average is 45 ÷ 6 = 7.5. Step 2: his overall score is 60%, and every paper has the same maximum. So the average share, 7.5, stands for 60%. Step 3: any paper with a ratio term below 7.5 is below 60%. Those are 5, 6 and 7, which is 3 papers. Options (a), (c) and (d) count wrongly. The papers with 8, 9 and 10 are above 60%.
Tip: when all papers carry the same maximum, the overall percentage equals the average paper. Simply compare each term with the average.
Answer as per the official UPSC answer key.
Read the passage
In our schools, we teach our children all that is there to know about physics, maths and history and what-have-you. But do we teach them about the bitter caste divide that plagues the country, about the spectre of famine that stalks large parts of our land, about gender sensitivity, about the possibility of atheism as a choice, etc. ? Equally important, do we teach them to ask questions, or do we teach them only to passively receive our wisdom ? From the cocooned world of school, suddenly, the adolescent finds himself/herself in the unfettered world of university. Here he/she is swept up in a turmoil of ideas, influences and ideologies. For someone who has been discouraged from asking questions and forming an opinion, this transition can be painful.
Which one of the following statements best reflects the central idea of the passage given above ?
Answer (d) & explanation
The central idea is that good citizens need social and life skills besides academic content (d). Step 1: the passage says schools teach physics, maths and history, but not caste, famine, gender or how to ask questions. Step 2: so the jump to university is painful. Schools must add life and social skills to subjects. That is (d). Step 3: option (a), curriculum versus parents' expectations, is not discussed. Option (b) contradicts the passage. Option (c) is too general; it misses the key point "in addition to academic content".
Tip: between a broad option and a specific one that matches the passage, choose the specific one. The best answer captures the passage's exact concern.
Answer as per the official UPSC answer key.
In a class, 60% of students are from India and 50% of the students are girls. If 30% of the Indian students are girls, then what percentage of foreign students are boys ?
Answer (d) & explanation
20% of foreign students are boys (d). Step 1: take 100 students. 60 are Indian, and 30% of them, 18, are girls. Step 2: total girls = 50, so foreign girls = 50 − 18 = 32. Foreign students = 100 − 60 = 40. So foreign boys = 40 − 32 = 8. Step 3: the question asks for a share of foreign students: 8 ÷ 40 = 20%. Option (a), 45%, and the others fail. Note 8% of the whole class is also a trap if you forget to divide by 40.
Tip: always check the base of the percentage. "Percentage of foreign students" means divide by the foreign total, not the class total.
"30% of the Indian students" is not 30% of the whole class.
Answer as per the official UPSC answer key.
Read the passage
Nothing can exist in a natural state which can be called good or bad by common assent, since every man who is in a natural state consults only his own advantage, and determines what is good or bad according to his own fancy and insofar as he has regard for his own advantage alone, and holds himself responsible to no one save himself by any law; and therefore sin cannot be conceived in a natural state, but only in a civil state, which is decreed by common consent what is good or bad, and each one holds himself responsible to the state.
Which one of the following statements best reflects the central idea of the passage given above ?
Answer (a) & explanation
The central idea is that ideas of right and wrong come from the formation of a state (a). Step 1: the passage says in a natural state each man judges good and bad by his own advantage. Nothing is good or bad "by common assent". Step 2: right and wrong are fixed by common consent "only in a civil state". That is (a). Step 3: option (b) says no man would be morally right without a ruler, which goes too far. Option (c) calls man immoral; but the passage says morality cannot even exist in a natural state. Option (d), survival of the species, is not discussed.
Tip: this is Spinoza's social-contract view. "Immoral" needs a moral standard; the passage says no shared standard exists before the state.
Answer as per the official UPSC answer key.
Read the passage
“...... most people would agree that telling deliberate lies is wrong, except perhaps in certain special situations where more harm will be done by telling the truth. Even the most truthful people probably tell a good many more lies that might be regarded as semantic lies; their use of words contains some measure of falsehood, more or less deliberate.”
Which one of the following habits is found more often in good people ?
Answer (b) & explanation
The habit found more often in good people is intentional mixing of truth with falsehood (b). Step 1: the passage says even the most truthful people tell "semantic lies". Their words contain "some measure of falsehood, more or less deliberate". Step 2: "deliberate" means intentional. So truth mixed with falsehood on purpose is (b). Step 3: option (a) leaves out the deliberate part. Options (c), falsifying facts, and (d), complete concealment, are much stronger than the passage's mild claim.
Tip: when two options look alike, find the word that separates them. Here "intentional" matches "deliberate" in the passage.
Answer as per the official UPSC answer key.
A woman runs 12 km towards her North, then 6 km towards her South and then 8 km towards her East. In which direction is she from her starting point ?
Answer (b) & explanation
She is at an angle less than 45° North of East (b). Step 1: 12 km North, then 6 km South, leaves her 6 km North. Then 8 km East. Step 2: so her net position is 6 km North and 8 km East. Step 3: the north part (6) is less than the east part (8). So the direction is closer to East: tan θ = 6/8, giving about 37° North of East, less than 45°. Options (a) and (c) wrongly say South. Option (d) says more than 45°.
Tip: if the two parts are equal, the angle is exactly 45°. The bigger part decides which direction the line leans towards.
Answer as per the official UPSC answer key.
Read the passage
Our cities are extremely vulnerable to climate change because of large concentrations of populations and poor infrastructure. Moreover, population densities are increasing in them but we have not yet developed the systems to address climate change impacts. Our cities contribute to 65 per cent of the GDP, but there are not enough facilities to cater to the needs of the people. It is important to address the issues of air quality, transport, etc., that are vital to identifying sustainable solutions. We need to involve citizens in city planning and create an ecosystem that meets the needs of the people.
Which among the following is the most logical and rational inference that can be made from the passage given above ?
Answer (c) & explanation
The best inference is that our cities need sustainability-related interventions to be maintained and developed (c). Step 1: the passage says cities are vulnerable to climate change. It says air quality, transport and citizen planning are "vital to identifying sustainable solutions". That is (c). Step 2: option (a), administrative autonomy, and option (d), PPP mode, are never mentioned. Step 3: option (b) calls rising density a hindrance to sustainable development. The passage mentions density only as one cause of vulnerability; it does not make it the main barrier.
Tip: pick the option that uses the passage's own keywords and conclusion. Options naming specific models (PPP, autonomy) are usually outside the text.
Answer as per the official UPSC answer key.
Read the passage
With respect to what are called denominations of religion, if everyone is left to be a judge of his own religion, there is no such thing as religion that is wrong; but if they are to be a judge of each other’s religion, there is no such thing as a religion that is right, and therefore all the world is right or all the world is wrong in the matter of religion.
What is the most logical assumption that can be made from the passage given above ?
Answer (c) & explanation
The most logical assumption is that religious denominations tend to ignore the unity of man (c). Step 1: the passage says if each judges his own religion, all are right. But if each judges the others', none is right. Each group sees only its own view, so they divide people instead of seeing what they share. That is (c). Step 2: option (a) says no one can live without a religion; the passage does not say this. Option (b), a duty to spread one's religion, is also not stated. Step 3: option (d) says men do not understand their own religion; the passage never doubts that.
Tip: an assumption must sit underneath the author's argument. Reject options that bring in duties or needs the passage never mentions.
Answer as per the official UPSC answer key.
There are three points P, Q and R on a straight line such that PQ : QR = 3 : 5. If n is the number of possible values of PQ : PR, then what is n equal to ?
Answer (b) & explanation
There are 2 possible values of PQ : PR (b). Step 1: take PQ = 3 and QR = 5. Draw the possible orders. Step 2: if Q lies between P and R, then PR = 3 + 5 = 8, giving 3 : 8. If P lies between Q and R, then PR = 5 − 3 = 2, giving 3 : 2. Step 3: R cannot lie between P and Q, because QR (5) is longer than PQ (3). So n = 2. Options (a), (c) and (d) miscount the cases.
Tip: for points on a line, list every possible order and test each one. A case is possible only if the lengths fit.
Answer as per the official UPSC answer key.
A Statement followed by Conclusion-I and Conclusion-II is given below. You have to take the Statement to be true even if it seems to be at variance from the commonly known facts. Read all Conclusions and then decide which of the given Conclusion(s) logically follows/follow from the Statement, disregarding the commonly known facts.
Statement : Some radios are mobiles. All mobiles are computers. Some computers are watches.
Conclusion-I : Certainly some radios are watches.
Conclusion-II : Certainly some mobiles are watches.
Which one of the following is correct ?
Answer (d) & explanation
Neither conclusion follows (d). Step 1: some radios are mobiles, and all mobiles are computers. The watches are linked only to "some computers". Step 2: those computers may be ones that are not mobiles and not radios. So we cannot be sure any radio or mobile is a watch. Step 3: conclusions I and II both say "certainly", so neither follows. Options (a), (b) and (c) fail.
Tip: "some A are B" and "some B are C" give no sure link between A and C. Draw the circles so that the watches touch computers away from mobiles. If such a drawing is possible, the "certain" conclusion fails.
The word 'certainly' needs a sure link; a 'some' link through a big group (computers) is not sure.
Answer as per the official UPSC answer key.
Read the passage
In the immediate future, we will see the increasing commodification of many new technologies — artificial intelligence and robotics, 3D manufacturing, custom made biological and pharmaceutical products, lethal autonomous weapons and driverless cars. This will pose conundrums. The moral question of how a driverless car will decide between hitting a jaywalker and swerving and damaging the car has often been debated. The answer is both simple — save the human life — and complex. At which angle should the car swerve — just enough to save the jaywalker or more than enough ? If the driverless car is in Dublin, who would take the decision ? The Irish Government, or the car’s original code writer in California, or a software programmer in Hyderabad to whom maintenance is outsourced ? If different national jurisdictions have different fine print on prioritising a human life, how will it affect insurance and investment decisions, including transnational ones ?
Which of the following statements best reflect the rational, plausible and practical implications that can be derived from the passage given above ?
- 1. Too much globalization is not in the best interests of any country.
- 2. Modern technologies are increasingly blurring the economic borders.
- 3. Innovation and capital have impinged on the domain of the State.
- 4. Public policy of every country should focus on developing its own supply chains.
- 5. Geopolitics will have to reconcile to many ambiguities and uncertainties.
Select the correct answer using the code given below :
Answer (c) & explanation
Implications 2, 3 and 5 are valid (c). Step 1: one driverless car involves Dublin, a code writer in California and a programmer in Hyderabad. Technology is blurring economic borders (2). Step 2: a code writer, not a government, may decide how the car swerves. Innovation and capital have entered the domain of the state (3). Step 3: different countries have different rules, which creates uncertainty for geopolitics, insurance and investment (5). Statements 1 (too much globalisation is bad) and 4 (build your own supply chains) are policy opinions the passage never gives. So options (a), (b) and (d) fail.
Tip: an implication follows from facts in the passage. Advice about what countries "should" do needs the author to argue it.
Answer as per the official UPSC answer key.
A pie diagram shows the percentage distribution of proteins, water and other dry elements in the human body. Given that proteins correspond to 16% and water corresponds to 70%. If both proteins and the other dry elements correspond to p%, then what is the central angle of the sector representing p on the pie diagram ?
Answer (c) & explanation
The central angle is 108° (c). Step 1: proteins are 16% and water is 70%. Everything else is the "other dry elements". Step 2: p% is proteins plus other dry elements, which is everything except water: 100 − 70 = 30%. Step 3: a full pie is 360°. So 30% of 360° = 108°. Option (a), 54°, uses only part of it. Options (b) and (d) use wrong percentages.
Tip: in a pie chart, 1% = 3.6°. Often the quickest route is to subtract the parts you don't need from 100%.
Answer as per the official UPSC answer key.
Read the passage
India faces a challenging immediate future in energy and climate policy-making. The problems are multiple : sputtering fossil fuel production capabilities; limited access to electricity and modern cooking fuel for the poorest; rising fuel imports in an unstable global energy context; continued electricity pricing and governance challenges leading to its costly deficits or surplus supply; and not least, growing environmental contestation around land, water and air. But all is not bleak: growing energy efficiency programmes; integrated urbanisation and transport policy discussions; inroads to enhancing energy access and security; and bold renewable energy initiatives, even if not fully conceptualised, suggest the promise of transformation.
Which one of the following statements best reflects the critical message conveyed by the passage given above ?
Answer (a) & explanation
The critical message is that India's energy decisions are becoming more complex and interlinked (a). Step 1: the passage lists many linked problems: supply, access, imports, pricing and environment. It also lists linked responses. So decision-making is complex. That is (a). Step 2: options (c) and (d) are too negative. The passage speaks of a "promise of transformation", not failure or a narrow supply focus. Step 3: option (b), policy heavily tuned to sustainable development goals, overstates what the passage says.
Tip: if a passage piles up many connected issues, the message is usually "complexity". Check the passage's tone before choosing a negative option.
Answer as per the official UPSC answer key.
Jay and Vijay spent an equal amount of money to buy some pens and special pencils of the same quality from the same store. If Jay bought 3 pens and 5 pencils, and Vijay bought 2 pens and 7 pencils, then which one of the following is correct ?
Answer (c) & explanation
A pen costs twice as much as a pencil (c). Step 1: both spent the same amount. So 3 pens + 5 pencils = 2 pens + 7 pencils. Step 2: take away 2 pens and 5 pencils from both sides. What is left: 1 pen = 2 pencils. Step 3: so a pen costs two times a pencil. Option (a) reverses it; option (b), equal prices, and option (d), three times, do not fit the equation.
Tip: when two purchases cost the same, cancel the common items. What remains is a direct price comparison, with no need for algebra.
Answer as per the official UPSC answer key.