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.
(Same information as the question above.)
Who wore the sweater ?
Answer (a) & explanation
A wore the sweater (a). Step 1: someone wore a white sweater. Clue 1 says B did not wear it. Clue 2 says C wore a tie. So the white sweater belongs to A. Step 2: this also fixes the rest. A is Kumar, C (Ribeiro) wears the blue tie, and B (Singh) wears the black jacket. Kumar does not wear a jacket, which fits A wearing the sweater. Step 3: so option (b) B wears the jacket, and option (c) C wears the tie. Option (d) fails because the answer is clear.
Tip: in linked puzzles, the first fact you work out often answers a later question directly. Write down each solved fact as you go.
Answer as per the official UPSC answer key.
Read the passage
Accountability, or the lack of it, in governance generally, and civil services, in particular, is a major factor underlying the deficiencies in governance and public administration. Designing an effective framework for accountability has been a key element of the reform agenda. A fundamental issue is whether civil services should be accountable to the political executive of the day or to society at large. In other words, how should internal and external accountability be reconciled ? Internal accountability is sought to be achieved by internal performance monitoring, official supervision by bodies like the Central Vigilance Commission and Comptroller and Auditor General, and judicial review of executive decisions. Articles 311 and 312 of the Indian Constitution provide job security and safeguards to the civil services, especially the All India Services. The framers of the Constitution had envisaged that provision of these safeguards would result in a civil service that is not totally subservient to the political executive but will have the strength to function in larger public interest. The need to balance internal and external accountability is thus built into the Constitution. The issue is where to draw the line. Over the years, the emphasis seems to have tilted in favour of greater internal accountability of the civil services to the political leaders of the day who in turn are expected to be externally accountable to the society at large through the election process. This system for seeking accountability to society has not worked out, and has led to several adverse consequences for governance.
Some special measures can be considered for improving accountability in civil services. Provisions of articles 311 and 312 should be reviewed and laws and regulations framed to ensure external accountability of civil services. The proposed Civil Services Bill seeks to address some of these requirements. The respective roles of professional civil services and the political executive should be defined so that professional managerial functions and management of civil services are depoliticized. For this purpose, effective statutory civil service boards should be created at the centre and in the states. Decentralization and devolution of authority to bring government and decision making closer to the people also helps to enhance accountability.
Which one of the following is the essential message implied by this passage ?
Answer (d) & explanation
The essential message is the need for reforms in civil service accountability (d). Step 1: the passage first explains the problem, then lists special measures: reviewing Articles 311 and 312, a Civil Services Bill and independent boards. A list of fixes means the message is reform. Step 2: option (a) is too absolute. Civil servants are accountable, only the balance is off. Step 3: option (b), about educated people avoiding politics, is not discussed. Option (c) is wrong because the framers did build in a balance through Articles 311 and 312.
Tip: the "essential message" usually sits where the author moves from the problem to the solution. Watch for words like "needs" or "measures".
Answer as per the official UPSC answer key.
(Same information as the question above.)
Which of the following statements is/are correct ?
Answer (b) & explanation
F is painted indigo (b). Step 1: A is orange, C is green, and E (golf) is violet. Indigo, blue and yellow are left for B, D and F. Step 2: F holds the hockey ball. The hockey ball is in neither the blue nor the yellow box. So F must be indigo. Step 3: B and D share blue and yellow, but no clue says which is which. So option (a), D yellow, and option (c), B blue, are only possible, not certain. Option (d), "all of the above", fails too.
Tip: "is/are correct" in puzzles means "must be correct". If a fact could go either way, it does not count as correct.
Answer as per the official UPSC answer key.
Read the passage
An increase in human-made carbon dioxide in the atmosphere could initiate a chain reaction between plants and microorganisms that would unsettle one of the largest carbon reservoirs on the planet — soil. In a study, it was found that the soil, which contains twice the amount of carbon present in all plants and Earth’s atmosphere combined, could become increasingly volatile as people add more carbon dioxide to the atmosphere. This is largely because of increased plant growth. Although a greenhouse gas and a pollutant, carbon dioxide also supports plant growth. As trees and other vegetation flourish in a carbon dioxide-rich future, their roots could stimulate microbial activity in soil that may in turn accelerate the decomposition of soil carbon and its release into the atmosphere as carbon dioxide.
Which among the following is the most logical corollary to the above passage ?
Answer (d) & explanation
The best corollary is that more green cover could release carbon trapped in soil (d). Step 1: the passage says thriving vegetation feeds soil microbes, which "accelerate the decomposition of soil carbon". When soil carbon breaks down, carbon dioxide is released. So more plants could release soil carbon. That is option (d). Step 2: option (b) says humans are solely responsible for carbon dioxide, which the passage contradicts. Step 3: option (c) reverses the cause: plants feed the microbes, not the other way. Option (a) is true but not the passage's point.
Tip: a corollary follows from the passage's chain of cause and effect. Trace the chain carefully, plants to microbes to soil carbon.
Answer as per the official UPSC answer key.
There are some nectar-filled flowers on a tree and some bees are hovering on it. If one bee lands on each flower, one bee will be left out. If two bees land on each flower, one flower will be left out. The number of flowers and bees respectively are :
Answer (c) & explanation
There are 3 flowers and 4 bees (c). Step 1: one bee per flower leaves one bee out. So bees = flowers + 1. Step 2: two bees per flower leaves one flower empty. So bees = 2 × (flowers − 1). Step 3: put them together: f + 1 = 2f − 2, so f = 3 and bees = 4. Check: 4 bees on 3 flowers leaves 1 bee over, and 2 bees each on 2 flowers uses all 4 bees with 1 flower empty. Option (a), 2 and 4, fails the first rule. Options (b) and (d) give fewer bees than flowers, which breaks the first rule.
Tip: you can skip the algebra by testing each option against both rules. The one that passes both is the answer.
(d) swaps the order. The question asks for flowers first.
Answer as per the official UPSC answer key.
Read the passage
To understand the nature and quantity of Government proper for man, it is necessary to attend to his character. As nature created him for social life, she fitted him for the station she intended. In all cases she made his natural wants greater than his individual powers. No one man is capable, without the aid of society, of supplying his own wants, and those wants, acting upon every individual, impel the whole of them into society.
Which among the following is the most logical and rational inference that can be made from the above passage ?
Answer (d) & explanation
The best inference is that many natural wants pushed people into society (d). Step 1: the passage says human wants are greater than one person's powers. These wants "impel the whole of them into society". That is option (d). Step 2: option (b) says every society is always short of its wants. But the passage says individuals, not societies, fall short. Step 3: option (c), that social life is special to humans, states a fact without the reason. Option (a), that nature created diversity, is not discussed.
Tip: an inference should keep the author's cause and effect. Here the cause is many wants and the effect is social life.
Answer as per the official UPSC answer key.
In a race, a competitor has to collect 6 apples which are kept in a straight line on a track and a bucket is placed at the beginning of the track which is a starting point. The condition is that the competitor can pick only one apple at a time, run back with it and drop it in the bucket. If he has to drop all the apples in the bucket, how much total distance he has to run if the bucket is 5 meters from the first apple and all other apples are placed 3 meters apart?
Answer (d) & explanation
He runs 150 m in total (d). Step 1: the first apple is 5 m from the bucket, and each next one is 3 m further. So the apples are at 5, 8, 11, 14, 17 and 20 m. Step 2: add them: 5 + 8 + 11 + 14 + 17 + 20 = 75 m. Step 3: for each apple, he runs out and back, so each trip is doubled. Total = 2 × 75 = 150 m. Option (c), 75 m, is the trap: it counts only one way. Options (a) and (b) do not fit.
Tip: in "pick and return" problems, every trip is a round trip. For evenly spaced items, the sum = number × (first + last) ÷ 2 = 6 × 25 ÷ 2 = 75.
75 m counts only one way.
Answer as per the official UPSC answer key.
Read the passage
We are witnessing a dangerous dwindling of biodiversity in our food supply. The green revolution is a mixed blessing. Over time farmers have come to rely heavily on broadly adapted, high yield crops to the exclusion of varieties adapted to the local conditions. Monocropping vast fields with the same genetically uniform seeds helps boost yield and meet immediate hunger needs. Yet high-yield varieties are also genetically weaker crops that require expensive chemical fertilizers and toxic pesticides. In our focus on increasing the amount of food we produce today, we have accidentally put ourselves at risk for food shortages in future.
Which among the following is the most logical and critical inference that can be made from the above passage ?
Answer (d) & explanation
The best inference is that the green revolution can threaten biodiversity and food security in the long run (d). Step 1: the passage calls the green revolution a "mixed blessing". Uniform high-yield crops cut biodiversity and may lead to "food shortages in future". Option (d) says exactly this. Step 2: option (a) says we use fertilisers "only due to green revolution". The word "only" goes too far. Option (c) says monocropping is "the only way" to food security, which the passage does not claim. Step 3: option (b) repeats a detail from the passage, not an inference.
Tip: a good inference joins the passage's warning to its consequence. Options with "only" are usually traps.
Answer as per the official UPSC answer key.
AB is a vertical trunk of a huge tree with A being the point where the base of the trunk touches the ground. Due to a cyclone, the trunk has been broken at C which is at a height of 12 meters, broken part is partially attached to the vertical portion of the trunk at C. If the end of the broken part B touches the ground at D which is at a distance of 5 meters from A, then the original height of the trunk is :
Answer (b) & explanation
The original height was 25 m (b). Step 1: the trunk breaks at C, 12 m high, and the top touches the ground 5 m from the base. The standing part (12 m), the ground distance (5 m) and the broken part form a right-angled triangle. Step 2: broken part = √(12 × 12 + 5 × 5) = √169 = 13 m. This is the 5-12-13 set. Step 3: original height = standing part + broken part = 12 + 13 = 25 m. Option (a), 20 m, and options (c) and (d) do not fit.
Tip: in broken-tree problems, the broken piece is the long side of the triangle. Add it back to the standing part to get the full height.
Answer as per the official UPSC answer key.
Read the passage
Accountability, or the lack of it, in governance generally, and civil services, in particular, is a major factor underlying the deficiencies in governance and public administration. Designing an effective framework for accountability has been a key element of the reform agenda. A fundamental issue is whether civil services should be accountable to the political executive of the day or to society at large. In other words, how should internal and external accountability be reconciled ? Internal accountability is sought to be achieved by internal performance monitoring, official supervision by bodies like the Central Vigilance Commission and Comptroller and Auditor General, and judicial review of executive decisions. Articles 311 and 312 of the Indian Constitution provide job security and safeguards to the civil services, especially the All India Services. The framers of the Constitution had envisaged that provision of these safeguards would result in a civil service that is not totally subservient to the political executive but will have the strength to function in larger public interest. The need to balance internal and external accountability is thus built into the Constitution. The issue is where to draw the line. Over the years, the emphasis seems to have tilted in favour of greater internal accountability of the civil services to the political leaders of the day who in turn are expected to be externally accountable to the society at large through the election process. This system for seeking accountability to society has not worked out, and has led to several adverse consequences for governance.
Some special measures can be considered for improving accountability in civil services. Provisions of articles 311 and 312 should be reviewed and laws and regulations framed to ensure external accountability of civil services. The proposed Civil Services Bill seeks to address some of these requirements. The respective roles of professional civil services and the political executive should be defined so that professional managerial functions and management of civil services are depoliticized. For this purpose, effective statutory civil service boards should be created at the centre and in the states. Decentralization and devolution of authority to bring government and decision making closer to the people also helps to enhance accountability.
According to the passage, which one of the following is not a means of enhancing internal accountability of civil services ?
Answer (d) & explanation
People's participation is not a means of internal accountability (d). Step 1: the passage lists the internal means: internal performance monitoring, supervision by bodies like the CVC and CAG, judicial review of executive decisions, and the job safeguards in Articles 311 and 312. Step 2: so options (a), (b) and (c) all appear in the passage as internal means. Step 3: involving people in decisions brings government "closer to the people". That is accountability to society, which is external accountability. So (d) is the odd one out.
Tip: for a "which is NOT" question, tick off every option the passage supports. The one left over is the answer. Read the question word "not" twice.
Answer as per the official UPSC answer key.
(Same information as the question above.)
The football is in the box of which colour ?
Answer (c) & explanation
The colour of the football box cannot be determined (c). Step 1: from the earlier steps, the football is in box D. Step 2: F is indigo, so D and B share blue and yellow. Step 3: no clue tells us whether D is blue or yellow. The hockey rule fixes only F. So option (a) yellow and option (d) blue are both possible but not certain. Option (b), indigo, is wrong because F is indigo.
Tip: when two items can swap places with no rule broken, the answer is "cannot be determined". Before you choose it, check that you have used every clue. Here no clue links D or B to blue or yellow.
Answer as per the official UPSC answer key.
Read the passage
Historically, the biggest challenge to world agriculture has been to achieve a balance between demand for and supply of food. At the level of individual countries, the demand-supply balance can be a critical policy issue for a closed economy, especially if it is a populous economy and its domestic agriculture is not growing sufficiently enough to ensure food supplies, on an enduring basis; it is not so much and not always, of a constraint for an open, and growing economy, which has adequate exchange surpluses to buy food abroad. For the world as a whole, supply-demand balance is always an inescapable prerequisite for warding off hunger and starvation. However, global availability of adequate supply does not necessarily mean that food would automatically move from countries of surplus to countries of deficit if the latter lack in purchasing power. The uneven distribution of hunger, starvation, under- or malnourishment, etc., at the world-level, thus owes itself to the presence of empty-pocket hungry mouths, overwhelmingly confined to the underdeveloped economies. Inasmuch as ‘a two-square meal’ is of elemental significance to basic human existence, the issue of worldwide supply of food has been gaining significance, in recent times; both because the quantum and the composition of demand has been undergoing big changes, and because, in recent years, the capabilities of individual countries to generate uninterrupted chain of food supplies have come under strain. Food production, marketing and prices, especially price-affordability by the poor in the developing world, have become global issues that need global thinking and global solutions.
According to the above passage, which of the following are the fundamental solutions for the world food security problem ?
- 1. Setting up more agro-based industries
- 2. Improving the price affordability by the poor
- 3. Regulating the conditions of marketing
- 4. Providing food subsidy to one and all
Select the correct answer using the code given below:
Answer (b) & explanation
Statements 2 and 3 are the fundamental solutions (b). Step 1: the closing line names "marketing and prices, especially price-affordability by the poor" as the key global issues. Step 2: so improving affordability for the poor (2) and regulating marketing conditions (3) are the solutions the passage points to. Step 3: setting up agro-based industries (1) and food subsidy for all (4) are not mentioned. So options (a), (c) and (d) fail.
Tip: "according to the passage" means stick to what is written. A food subsidy for "one and all" also sounds extreme; the passage stresses the poor. In India, the National Food Security Act targets about two-thirds of the population, not everyone.
Answer as per the official UPSC answer key.
There are five persons in a group — P, Q, R, S and T. The group has one doctor, one lawyer and one artist. P and S are unmarried students. T is a man married to one of the group members. Q is the brother of P and is neither doctor nor artist. R is not doctor.
Who is the doctor ?
Answer (a) & explanation
T is the doctor (a). Step 1: P and S are students, so they have no jobs. The doctor, lawyer and artist must be Q, R and T. Step 2: Q is neither the doctor nor the artist, so Q is the lawyer. Step 3: R is not the doctor, so R is the artist. That leaves T as the doctor. Options (b) P and (d) R are ruled out above, and (c) Q is the lawyer.
Tip: in grid puzzles, first remove the people who cannot hold any job. Then use the "is not" clues one at a time. Each clue usually fixes one more person. Make a small table of names and jobs and cross out boxes as you go.
Answer as per the official UPSC answer key.
Read the passage
The nature of the legal imperatives in any given state corresponds to the effective demands that state encounters, and that these, in their turn, depend, in a general way, upon the manner in which economic power is distributed in the society which the state controls.
The statement refers to :
Answer (b) & explanation
The statement shows the link between politics and economics (b). Step 1: it says laws follow the demands made on the state, and these depend "in a general way" on how economic power is spread. Step 2: so economics shapes politics, but only in a general way. That is a two-way relationship, not full control. Step 3: options (c) and (d) speak of one dominating the other, which "in a general way" does not support. Option (a), opposition between the two, is nowhere suggested.
Tip: soft words like "in a general way" or "to some extent" signal a link, not dominance. Choose the milder option when the author hedges.
Answer as per the official UPSC answer key.
A round archery target of diameter 1 m is marked with four scoring regions from the centre outwards as red, blue, yellow and white. The radius of the red band is 0.20 m. The width of all the remaining bands is equal. If archers throw arrows towards the target, what is the probability that the arrows fall in the red region of the archery target ?
Answer (c) & explanation
The probability of hitting red is 0.16 (c). Step 1: the target's diameter is 1 m, so its radius is 0.5 m. The red circle's radius is 0.2 m. Step 2: probability = red area ÷ whole area = π × 0.2² ÷ π × 0.5². The π cancels. Step 3: = (0.2 ÷ 0.5)² = 0.4² = 0.16. Option (a), 0.40, compares radii instead of areas. Option (b), 0.20, compares the red radius with the diameter. Option (d), 0.04, is just 0.2².
Tip: area grows with the square of the radius. When comparing circles, square the ratio of their radii. The widths of the other bands do not matter here.
the areas go with the square of the radius, so 0.2/0.5 = 0.4 is the trap.
Answer as per the official UPSC answer key.
A class starts at 11:00 am and lasts till 2:27 pm. Four periods of equal duration are held during this interval. After every period, a rest of 5 minutes is given to the students. The exact duration of each period is :
Answer (a) & explanation
Each period lasts 48 minutes (a). Step 1: from 11:00 am to 2:27 pm is 3 hours 27 minutes = 207 minutes. Step 2: four periods have three breaks between them, because the class ends with the last period. Breaks = 3 × 5 = 15 minutes. Step 3: 4 periods = 207 − 15 = 192 minutes, so each period = 192 ÷ 4 = 48 minutes. Counting four breaks by mistake gives about 46.75 minutes, which matches no option. Options (b), (c) and (d) are all too long.
Tip: in "gaps between items" problems, n items have n − 1 gaps, like fence posts. Check: 4 × 48 + 15 = 207, which matches.
counting 4 breaks gives 46·75, which is not an option. That tells you the last break is not inside the class time.
Answer as per the official UPSC answer key.
A person walks 12 km due north, then 15 km due east, after that 19 km due west and then 15 km due south. How far is he from the starting point ?
Answer (a) & explanation
He is 5 km from the start (a). Step 1: north–south: 12 km north, then 15 km south, leaves him 3 km south of the start. Step 2: east–west: 15 km east, then 19 km west, leaves him 4 km west. Step 3: 3 km south and 4 km west form a right angle. The straight-line distance is √(3 × 3 + 4 × 4) = √25 = 5 km. Option (b), 9 km, does not fit. Option (c), 37 km, adds some of the walks. Option (d), 61 km, adds all four walks, which is total distance, not displacement.
Tip: "how far from the start" means straight-line distance. Cancel opposite directions first, then use the right-angle rule.
Answer as per the official UPSC answer key.
Read the passage
In general, religious traditions stress our duty to god, or to some universal ethical principle. Our duties to one another derive from these. The religious concept of rights is primarily derived from our relationship to this divinity or principle and the implication it has on our other relationships. This correspondence between rights and duties is critical to any further understanding of justice. But, for justice to be practiced; virtue, rights and duties cannot remain formal abstractions. They must be grounded in a community (common unity) bound together by a sense of common union (communion). Even as a personal virtue, this solidarity is essential to the practice and understanding of justice.
With reference to the passage, the following assumptions have been made :
- 1. Human relationships are derived from their religious traditions
- 2. Human beings can be duty bound only if they believe in god
- 3. Religious traditions are essential to practice and understand justice
Which of these assumption(s) is/are valid ?
Answer (a) & explanation
Only assumption 1 is valid (a). Step 1: the passage says "our duties to one another derive from these" religious traditions. So human relationships are drawn from religious traditions, and assumption 1 holds. Step 2: assumption 2 says duty is possible only through belief in god. But the passage allows duty to "some universal ethical principle" too. The word only makes 2 wrong. Step 3: assumption 3 says religion is essential to justice. The passage calls the balance of rights and duties, and solidarity, essential, not religion. So options (b), (c) and (d) fail.
Tip: words like only, always and essential often turn a statement false. Check whether the passage really goes that far.
Answer as per the official UPSC answer key.
Two numbers X and Y are respectively 20% and 28% less than a third number Z. By what percentage is the number Y less than the number X?
Answer (b) & explanation
Y is 10% less than X (b). Step 1: take Z = 100. Then X is 20% less, so X = 80. Y is 28% less, so Y = 72. Step 2: Y is 80 − 72 = 8 less than X. Step 3: the question asks how much less than X, so the base is X. 8 ÷ 80 = 10%. Option (d), 8%, is the trap: it divides by 100, the base of Z. Option (a), 12%, and option (c), 9%, do not fit.
Tip: in percentage comparisons, always divide by the number after "than". Taking 100 as the starting value makes these questions quick.
28 – 20 = 8% uses Z as the base.
Answer as per the official UPSC answer key.
Read the passage
Historically, the biggest challenge to world agriculture has been to achieve a balance between demand for and supply of food. At the level of individual countries, the demand-supply balance can be a critical policy issue for a closed economy, especially if it is a populous economy and its domestic agriculture is not growing sufficiently enough to ensure food supplies, on an enduring basis; it is not so much and not always, of a constraint for an open, and growing economy, which has adequate exchange surpluses to buy food abroad. For the world as a whole, supply-demand balance is always an inescapable prerequisite for warding off hunger and starvation. However, global availability of adequate supply does not necessarily mean that food would automatically move from countries of surplus to countries of deficit if the latter lack in purchasing power. The uneven distribution of hunger, starvation, under- or malnourishment, etc., at the world-level, thus owes itself to the presence of empty-pocket hungry mouths, overwhelmingly confined to the underdeveloped economies. Inasmuch as ‘a two-square meal’ is of elemental significance to basic human existence, the issue of worldwide supply of food has been gaining significance, in recent times; both because the quantum and the composition of demand has been undergoing big changes, and because, in recent years, the capabilities of individual countries to generate uninterrupted chain of food supplies have come under strain. Food production, marketing and prices, especially price-affordability by the poor in the developing world, have become global issues that need global thinking and global solutions.
According to the above passage, the biggest challenge to world agriculture is :
Answer (d) & explanation
The biggest challenge is to balance the demand for and supply of food (d). Step 1: the first sentence says: "the biggest challenge to world agriculture has been to achieve a balance between demand for and supply of food". Option (d) matches it word for word. Step 2: option (a), finding land and expanding food processing, is not called the biggest challenge. Step 3: option (b), ending hunger in poor countries, is a result of the imbalance, not the challenge named. Option (c), balancing food and non-food production, is not discussed.
Tip: when the passage states the answer directly, pick the option closest to its words. Do not overthink "biggest challenge" questions.
Answer as per the official UPSC answer key.