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
“In simple matters like shoe-making, we think only a specially trained person will serve our purpose, but in politics, we presume that everyone who knows how to get votes knows how to administer a State. When we are ill, we call for a trained physician, whose degree is a guarantee of specific preparation and technical competence—we do not ask for the handsomest physician, or the most eloquent one : well then, when the whole State is ill should we not look for the service and guidance of the wisest and the best?”
Which one of the following statements best reflects the message of the author of the passage?
Answer (c) & explanation
The author's message is that we need a way to bar incompetence from public office (c). Step 1: the passage says we want a trained shoemaker and a trained doctor. Yet in politics we assume anyone who can get votes can run a State. Step 2: it ends: when the State is ill, we should seek "the wisest and the best". So incompetence must be kept out. That is (c). Step 3: option (a) is the assumption the author criticises. Option (b), only administrators, is narrower than his point. Option (d) goes against the passage.
Tip: this is Plato's argument in the Republic. Don't pick the view the author attacks; pick the one he argues for.
Answer as per the official UPSC answer key.
Read the passage
The demographic dividend, which has begun in India and is expected to last another few decades, is a great window of opportunity. The demographic dividend is basically a swelling in the working age population, which conversely means that the relative ratio of very young and very old will, for a while, be on the decline. From the experience of Ireland and China, we know that this can be a source of energy and an engine of economic growth. The demographic dividend tends to raise a nation’s savings rate since in any nation, it is the working age population that is the main saver. And since the savings rate is an important driver of growth, this should help elevate our growth rate. However, the benefits of demographic dividend depend on the quality of the working age population. And this implies bringing back the importance of education, acquisition of skills and human capital.
Which of the following would invariably happen in a country, when the demographic dividend has begun to operate?
- 1. The number of illiterate people will decrease.
- 2. The ratio of very old and very young will decrease for a while.
- 3. Population growth rate will quickly stabilize.
Select the correct answer using the code given below.
Answer (b) & explanation
Only statement 2 happens invariably (b). Step 1: the passage defines the demographic dividend as a swelling working-age population. It says this means the ratio of very young and very old will decline "for a while" (2). That always happens by definition. Step 2: statement 1, fewer illiterates, depends on policy. The passage says benefits depend on education, not that literacy rises automatically. Step 3: statement 3, population growth stabilising quickly, is not mentioned. So options (a), (c) and (d) fail.
Tip: "invariably" means always. Only what is true by definition passes; outcomes that need policy action do not.
Answer as per the official UPSC answer key.
What is the value of X in the sequence 2, 12, 36, 80, 150, X?
Answer (b) & explanation
X is 252 (b). Step 1: look for a pattern: 2 = 1 × 2, 12 = 4 × 3, 36 = 9 × 4, 80 = 16 × 5, 150 = 25 × 6. Step 2: each term is n² × (n + 1). Step 3: the next term is 6² × 7 = 36 × 7 = 252. Options (a) 248, (c) 258 and (d) 262 do not fit this pattern.
Tip: when terms grow fast but not by a fixed ratio, try squares or cubes times a simple number. Here n² × (n + 1) = n³ + n².
Answer as per the official UPSC answer key.
Read the passage
In some places in the world, the productivity of staples such as rice and wheat has reached a plateau. Neither new strains nor fancy agrochemicals are raising the yields. Nor is there much unfarmed land left that is suitable to be brought under the plough. If global temperature continues to rise, some places will become unsuitable for farming. Application of technology can help overcome these problems. Agricultural technology is changing fast. Much of this change is brought about by affluent farmers in the West/Americas. Techniques developed in the West are being adapted in some places to make tropical crops more productive. Technology is of little use if it is not adapted. In the developing world, that applies as much to existing farming techniques as it does to the latest advances in genetic modification. Extending to the smallholders and subsistence farmers of Africa and Asia the best of today’s agricultural practices, in such simple matters as how much fertilizers to apply and when, would lead to a greatly increased availability of food for humanity. So would things like better roads and storage facilities, to allow for the carriage of surpluses to markets and reduce wastage.
Based on the above passage, the following assumptions have been made :
- 1. Poor countries need to bring about change in their existing farming techniques.
- 2. Developed countries have better infrastructure and they waste less food.
Which of the above assumptions is/are valid?
Answer (a) & explanation
Only assumption 1 is valid (a). Step 1: the passage says spreading "the best of today's agricultural practices" to smallholders in Africa and Asia would greatly increase food. This assumes poor countries must change their current farming methods (1). Step 2: it mentions roads and storage to cut wastage, but it never compares developed and poor countries on infrastructure or waste (2). Step 3: so options (b), (c) and (d) fail.
Tip: an assumption must be needed for the author's argument. A comparison the author never makes cannot be an assumption.
Answer as per the official UPSC answer key.
Let A, B and C represent distinct non-zero digits. Suppose x is the sum of all possible 3-digit numbers formed by A, B and C without repetition.
Consider the following statements :
- 1. The 4-digit least value of x is 1332.
- 2. The 3-digit greatest value of x is 888.
Which of the above statements is/are correct?
Answer (a) & explanation
1. Six numbers can be made (ABC, ACB, BAC, BCA, CAB, CBA). Each digit sits twice in the hundreds place, twice in the tens and twice in the units.
2. So x = 222 × (A + B + C). Check with 1, 2, 3: 123 + 132 + 213 + 231 + 312 + 321 = 1332, and 222 × 6 = 1332.
3. The smallest A + B + C is 1 + 2 + 3 = 6, so the smallest x is 1332. Statement 1 is true.
4. Since x is at least 1332, it is never a 3-digit number. Statement 2 is false.
Answer as per the official UPSC answer key.
Read the passage
The main threat to maintaining progress in human development comes from the increasingly evident unsustainability of production and consumption patterns. Current production models rely heavily on fossil fuels. We now know that this is unsustainable because the resources are finite. The close link between economic growth and greenhouse gas emissions needs to be severed for human development to become truly sustainable. Some developed countries have begun to alleviate the worst effects by expanding recycling and investing in public transport and infrastructure. But most developing countries are hampered by the high costs and low availability of clean energy sources. Developed countries need to support developing countries’ transition to sustainable human development.
Unsustainability in production pattern is due to which of the following?
- 1. Heavy dependence on fossil fuels
- 2. Limited availability of resources
- 3. Expansion of recycling
Select the correct answer using the code given below.
Answer (a) & explanation
Statements 1 and 2 are the causes (a). Step 1: the passage says current production "relies heavily on fossil fuels" (1). Step 2: it says this is unsustainable "because the resources are finite", meaning limited (2). Step 3: recycling appears as something developed countries do to reduce the harm. It is a remedy, not a cause, so statement 3 fails. That rules out options (c) and (d). Option (b) misses statement 1.
Tip: in cause questions, separate the problem from the cure. A passage often mentions both, and UPSC places the cure among the causes as a trap.
Answer as per the official UPSC answer key.
Read the passage
Natural selection cannot anticipate future environments on the earth. Therefore, the set of existing organisms can never be fully prepared for environmental catastrophes that await life. An outcome of this is the extinction of those species which cannot overcome environmental adversity. This failure to survive, in modern terms, can be attributed to the genomes which are unable to withstand geological vagaries or biological mishaps (infections, diseases and so on). In biological evolution on the earth, extinction of species has been a major feature. The earth may presently have up to ten million species, yet more than 90% of species that have ever lived on the earth are now extinct. Once again, the creationist doctrines fail to satisfactorily address why a divine creator will firstly bother to create millions of species and then allow them to perish. The Darwinian explanation for extinct life is once again simple, elegant and at once convincing—organisms go extinct as a function of environmental or biological assaults for which their inheritance deems them ill-equipped. Therefore, the so-called Darwinian theory of evolution is not a theory at all. Evolution happens—this is a fact. The mechanism of evolution (Darwin proposed natural selection) is amply supported by scientific data. Indeed, to date no single zoological, botanical, geological, paleontological, genetic or physical evidence has refuted either of the central two main Darwinian ideas. If religion is not taken into consideration, Darwinian laws are acceptable just like the laws proposed by Copernicus, Galileo, Newton and Einstein—sets of natural laws that explain natural phenomena in the universe.
With reference to the passage, the following assumptions have been made :
- 1. Only species that have the ability to overcome environmental catastrophes will survive and perpetuate.
- 2. More than 90% of the species on the earth are in the danger of getting extinct due to drastic changes in the environment.
- 3. Darwin’s theory explains all the natural phenomena.
Which of the above assumptions is/are valid?
Answer (a) & explanation
Only assumption 1 is valid (a). Step 1: the passage says species that cannot overcome environmental adversity go extinct. So only those that can overcome it survive (1). Step 2: assumption 2 misreads the 90% figure. The passage says 90% of species that ever lived are now extinct, not that 90% of today's species are in danger. Step 3: assumption 3 says Darwin's theory explains all natural phenomena; this overreaches. So options (b), (c) and (d) fail.
Tip: check what a number refers to. UPSC often changes "species that ever lived" into "species on earth now" to set a trap.
Answer as per the official UPSC answer key.
What is the smallest number greater than 1000 that when divided by any one of the numbers 6, 9, 12, 15, 18 leaves a remainder of 3?
Answer (c) & explanation
The number is 1083 (c). Step 1: a number leaving remainder 3 for each divisor is 3 more than a common multiple. LCM(6, 9, 12, 15, 18) = 180. Step 2: so the number is 180k + 3. Step 3: 180 × 5 + 3 = 903 is below 1000. 180 × 6 + 3 = 1083 is the first above 1000. Options (a) 1063 and (b) 1073 are not 3 more than a multiple of 180. Option (d), 1183, is not either.
Tip: "same remainder r for all divisors" means the number = LCM × k + r. Find the LCM first.
Answer as per the official UPSC answer key.
Read the passage
The poverty line is quite unsatisfactory when it comes to grasping the extent of poverty in India. It is not only because of its extremely narrow definition of ‘who is poor’ and the debatable methodology used to count the poor, but also because of a more fundamental assumption underlying it. It exclusively relies on the notion of poverty as insufficient income or insufficient purchasing power. One can better categorize it by calling it income poverty. If poverty is ultimately about deprivations affecting human well-being, then income poverty is only one aspect of it. Poverty of a life, in our view, lies not merely in the impoverished state in which the person actually lives, but also in the lack of real opportunity given by social constraints as well as personal circumstances—to choose other types of living. Even the relevance of low incomes, meagre possessions, and other aspects of what are standardly seen as economic poverty relate ultimately to their role in curtailing capabilities, i.e., their role in severely restricting the choices people have to lead variable and valued lives.
Why is the methodology adopted in India to count the ‘poor’ debatable?
Answer (d) & explanation
The method is debatable because it rests only on poverty as low income or buying power (d). Step 1: the passage says the poverty line "exclusively relies on the notion of poverty as insufficient income or insufficient purchasing power". Step 2: this narrow base is the fundamental problem. That is (d). Step 3: option (a), confusion over the line, is not the stated reason. Option (b), rural-urban diversity, and option (c), lack of a global standard, are outside the passage.
Tip: this passage draws on Amartya Sen's capability approach. India's NITI Aayog now also uses a Multidimensional Poverty Index alongside income measures.
Answer as per the official UPSC answer key.
Read the passage
The demographic dividend, which has begun in India and is expected to last another few decades, is a great window of opportunity. The demographic dividend is basically a swelling in the working age population, which conversely means that the relative ratio of very young and very old will, for a while, be on the decline. From the experience of Ireland and China, we know that this can be a source of energy and an engine of economic growth. The demographic dividend tends to raise a nation’s savings rate since in any nation, it is the working age population that is the main saver. And since the savings rate is an important driver of growth, this should help elevate our growth rate. However, the benefits of demographic dividend depend on the quality of the working age population. And this implies bringing back the importance of education, acquisition of skills and human capital.
With reference to the passage, which of the following inferences can be drawn?
- 1. Demographic dividend is an essential condition for a country to rapidly increase its economic growth rate.
- 2. Promotion of higher education is an essential condition for a country for its rapid economic growth.
Select the correct answer using the code given below.
Answer (d) & explanation
Neither inference can be drawn (d). Step 1: the passage says the demographic dividend "can be" an engine of growth. It does not say growth is impossible without it. So it is not an essential condition (1 fails). Step 2: the passage stresses education, skills and human capital in general. It does not single out higher education as essential (2 fails). Step 3: so options (a), (b) and (c) fail.
Tip: "can be a source" is not "is a necessary condition". India's working-age population share is expected to stay high for the next few decades, making skills the key.
Answer as per the official UPSC answer key.
One non-zero digit, one vowel and one consonant from English alphabet (in capital) are to be used in forming passwords, such that each password has to start with a vowel and end with a consonant. How many such passwords can be generated?
Answer (c) & explanation
945 passwords can be made (c). Step 1: the password starts with a vowel and ends with a consonant. So the order is fixed: vowel, digit, consonant. Step 2: there are 5 vowels, 9 non-zero digits and 21 consonants. Step 3: 5 × 9 × 21 = 945. Option (d), 1050, uses 10 digits (including 0). Options (a) and (b) leave out a factor.
Tip: when positions are fixed, simply multiply the choices for each place. Check "non-zero" carefully: it removes one digit.
Answer as per the official UPSC answer key.
Read the passage
In some places in the world, the productivity of staples such as rice and wheat has reached a plateau. Neither new strains nor fancy agrochemicals are raising the yields. Nor is there much unfarmed land left that is suitable to be brought under the plough. If global temperature continues to rise, some places will become unsuitable for farming. Application of technology can help overcome these problems. Agricultural technology is changing fast. Much of this change is brought about by affluent farmers in the West/Americas. Techniques developed in the West are being adapted in some places to make tropical crops more productive. Technology is of little use if it is not adapted. In the developing world, that applies as much to existing farming techniques as it does to the latest advances in genetic modification. Extending to the smallholders and subsistence farmers of Africa and Asia the best of today’s agricultural practices, in such simple matters as how much fertilizers to apply and when, would lead to a greatly increased availability of food for humanity. So would things like better roads and storage facilities, to allow for the carriage of surpluses to markets and reduce wastage.
Based on the above passage, the following assumptions have been made :
- 1. Growing enough food for future generations will be a challenge.
- 2. Corporate farming is a viable option for food security in poor countries.
Which of the above assumptions is/are valid?
Answer (a) & explanation
Only assumption 1 is valid (a). Step 1: the passage says yields have plateaued, little spare land is left, and warming may make places unfit for farming. So growing enough food in future will be a challenge (1). Step 2: the passage favours helping smallholders and subsistence farmers. Corporate farming is never raised (2). Step 3: so options (b), (c) and (d) fail.
Tip: if the passage's solution is "help small farmers", an option pushing a different model (corporate farming) is outside it.
Answer as per the official UPSC answer key.
There is a numeric lock which has a 3-digit PIN. The PIN contains digits 1 to 7. There is no repetition of digits. The digits in the PIN from left to right are in decreasing order. Any two digits in the PIN differ by at least 2. How many maximum attempts does one need to find out the PIN with certainty?
Answer (c) & explanation
At most 10 attempts are needed (c). Step 1: the digits go from big to small. So once three digits are chosen, the PIN is fixed. We only need to count the choices. Step 2: list sets from 1 to 7 where any two digits differ by at least 2: 531, 631, 641, 642, 731, 741, 742, 751, 752, 753. Step 3: that is 10 PINs, so 10 attempts make it certain. Options (a), (b) and (d) miscount.
Tip: when order is forced (decreasing), arrangements become combinations. A shortcut: choose 3 from 7 with gaps of 2 = C(5, 3) = 10.
Answer as per the official UPSC answer key.
Read the passage
The main threat to maintaining progress in human development comes from the increasingly evident unsustainability of production and consumption patterns. Current production models rely heavily on fossil fuels. We now know that this is unsustainable because the resources are finite. The close link between economic growth and greenhouse gas emissions needs to be severed for human development to become truly sustainable. Some developed countries have begun to alleviate the worst effects by expanding recycling and investing in public transport and infrastructure. But most developing countries are hampered by the high costs and low availability of clean energy sources. Developed countries need to support developing countries’ transition to sustainable human development.
Consider the following statements :
Developed countries can support developing countries’ transition to sustainable human development by
- 1. making clean energy sources available at low cost
- 2. providing loans for improving their public transport at nominal interest rates
- 3. encouraging them to change their production and consumption patterns
Which of the statements given above is/are correct?
Answer (b) & explanation
Statements 1 and 2 are correct (b). Step 1: the passage says developing countries face "high costs and low availability of clean energy". So making clean energy cheap and available helps them (1). Step 2: it says developed countries have eased harm by investing in public transport. Low-interest loans for this are real support (2). Step 3: statement 3, merely encouraging change, gives no material help. The passage asks developed countries to "support" the transition. So options (a), (c) and (d) fail.
Tip: "support" in such passages means money, technology or cheaper access. Advice alone is not support. India's climate stance also stresses finance and technology transfer from developed nations.
Answer as per the official UPSC answer key.
Read the passage
With steady economic growth, higher literacy and increasing skill levels, the number of Indian middle-class families has gone up exponentially. Direct results of the affluence have been changes in dietary patterns and energy consumption levels. People have moved to a higher protein-based diet like milk products, fish and meat, all of which need significantly more water to produce than cereal-based diets. Increasing use of electronic and electric machines/gadgets and motor vehicles needs more and more energy and generation of energy needs water.
Which one of the following statements best reflects the crux of the passage?
Answer (d) & explanation
The crux is that India's water management must change dramatically (d). Step 1: the passage says growing affluence changed diets toward milk, fish and meat, which need much more water than cereals. Step 2: it says more gadgets and vehicles need more energy, and making energy needs water. Both changes push water demand up, so water management must change. That is (d). Step 3: option (a) asks people to go back to cereal diets, which the passage does not suggest. Option (b) misses water. Option (c) is too general.
Tip: find the common thread in the examples. Diet and energy both lead to one word here: water.
Answer as per the official UPSC answer key.
Let p be a two-digit number and q be the number consisting of same digits written in reverse order. If p × q = 2430, then what is the difference between p and q?
Answer (d) & explanation
The difference is 9 (d). Step 1: p and q use the same two digits in reverse. Their product 2430 ends in 0, so one digit must be 5 and the other even (or one digit 0, which is not possible here). Step 2: try 45 × 54 = 2430. It works. Step 3: the difference is 54 − 45 = 9. Options (a), (b) and (c) do not fit.
Tip: a two-digit number and its reverse always differ by a multiple of 9 (9 × the difference of digits). Here the digits differ by 1, so the gap is 9.
Answer as per the official UPSC answer key.
Read the passage
The poverty line is quite unsatisfactory when it comes to grasping the extent of poverty in India. It is not only because of its extremely narrow definition of ‘who is poor’ and the debatable methodology used to count the poor, but also because of a more fundamental assumption underlying it. It exclusively relies on the notion of poverty as insufficient income or insufficient purchasing power. One can better categorize it by calling it income poverty. If poverty is ultimately about deprivations affecting human well-being, then income poverty is only one aspect of it. Poverty of a life, in our view, lies not merely in the impoverished state in which the person actually lives, but also in the lack of real opportunity given by social constraints as well as personal circumstances—to choose other types of living. Even the relevance of low incomes, meagre possessions, and other aspects of what are standardly seen as economic poverty relate ultimately to their role in curtailing capabilities, i.e., their role in severely restricting the choices people have to lead variable and valued lives.
Why is income poverty only one measure of counting the ‘poor’ ?
Answer (a) & explanation
Income poverty is only one measure because it covers only one kind of deprivation (a). Step 1: the passage says poverty is about all "deprivations affecting human well-being". Income poverty is "only one aspect" of it. So it ignores other deprivations. That is (a). Step 2: option (b) says other deprivations have nothing to do with income. But the passage says low income matters because it curtails capabilities. Step 3: options (c) and (d) talk about time (permanent, at one point). The passage says nothing about time.
Tip: options with "nothing to do with" are absolute. Check whether the passage links the two ideas; here it clearly does.
Answer as per the official UPSC answer key.
Five friends P, Q, X, Y and Z purchased some notebooks. The relevant information is given below :
- 1. Z purchased 8 notebooks more than X did.
- 2. P and Q together purchased 21 notebooks.
- 3. Q purchased 5 notebooks less than P did.
- 4. X and Y together purchased 28 notebooks.
- 5. P purchased 5 notebooks more than X did.
If each notebook is priced ₹ 40, then what is the total cost of all the notebooks?
Answer (a) & explanation
The total cost is ₹ 2,600 (a). Step 1: P + Q = 21 and Q = P − 5. So 2P − 5 = 21, giving P = 13 and Q = 8. Step 2: P bought 5 more than X, so X = 8. Z bought 8 more than X, so Z = 16. X + Y = 28, so Y = 20. Step 3: total = 13 + 8 + 8 + 20 + 16 = 65 notebooks. 65 × ₹ 40 = ₹ 2,600. Options (b), (c) and (d) come from wrong values.
Tip: start with the pair of equations that has only two unknowns (P and Q). Each answer then unlocks the next person.
Answer as per the official UPSC answer key.
There are 9 cups placed on a table arranged in equal number of rows and columns out of which 6 cups contain coffee and 3 cups contain tea. In how many ways can they be arranged so that each row should contain at least one cup of coffee?
Answer (d) & explanation
There are 81 ways (d). Step 1: the cups form a 3 × 3 grid. Placing the 3 tea cups decides everything. The number of ways to pick 3 places from 9 = 9 × 8 × 7 ÷ (3 × 2 × 1) = 84. Step 2: a row has no coffee only if all 3 tea cups fill that one row. This can happen in 3 ways (one per row). Step 3: 84 − 3 = 81. Options (a), (b) and (c) miscount.
Tip: for "at least one" conditions, count all cases and subtract the bad ones. It is usually easier than counting the good ones directly.
Answer as per the official UPSC answer key.
The letters A, B, C, D and E are arranged in such a way that there are exactly two letters between A and E. How many such arrangements are possible?
Answer (c) & explanation
There are 24 arrangements (c). Step 1: five places in a row. With exactly two letters between them, A and E can be at places (1, 4) or (2, 5). Step 2: in each pair, A and E can swap. So 2 pairs × 2 = 4 ways to place A and E. Step 3: the other three letters fill the three free places in 3 × 2 × 1 = 6 ways. Total = 4 × 6 = 24. Options (a), (b) and (d) miss the swap or the extra pair.
Tip: place the restricted letters first, remember they can swap, then arrange the rest freely.
Answer as per the official UPSC answer key.