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
It is certain, that seditions, wars, and contempt or breach of the laws are not so much to be imputed to the wickedness of the subjects, as to the bad state of a dominion. For men are not born fit for citizenship, but must be made so. Besides, men’s natural passions are everywhere the same; and if wickedness more prevails, and more offences are committed in one commonwealth than in another, it is certain that the former has neither enough pursued the end of unity, nor framed its laws with sufficient forethought; and that, therefore, it has failed in making quite good its right as a commonwealth.
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 the best dominion pursues unity and has laws for good citizenship (c). Step 1: the passage says trouble comes from a state that has not pursued the end of unity nor framed laws with forethought. So a good state does both. That is (c). Step 2: option (b) says the sovereign is responsible for all problems. But the passage says "not so much" the subjects, which is softer. Step 3: option (a) calls wars inevitable, and option (d) calls a good state impossible. The passage says the opposite: men can be "made" fit for citizenship.
Tip: watch for absolute words like "all", "inevitable" and "impossible". The passage's mild wording ("not so much") rarely supports them.
Answer as per the official UPSC answer key.
On a chess board, in how many different ways can 6 consecutive squares be chosen on the diagonals along a straight path ?
Answer (b) & explanation
There are 6 ways (b). Step 1: a chess board has two main diagonals with 8 squares each. Step 2: a straight run of 6 squares on a diagonal of 8 can start at square 1, 2 or 3. That gives 3 ways on each diagonal. Step 3: two diagonals × 3 = 6. Option (a), 4, and the bigger options (c) 8 and (d) 12 do not match this count. UPSC's key counts only the two main diagonals here.
Tip: the number of runs of length k in a line of n squares is n − k + 1. Here 8 − 6 + 1 = 3.
Answer as per the official UPSC answer key.
Read the passage
Fig trees (genus Ficus) are considered sacred in India, East Asia and Africa and are common in agricultural and urban landscapes where other large trees are absent. In natural forests, fig trees provide food for wildlife when other resources are scarce and support a high density and diversity of frugivores (fruit-eating animals). If frugivorous birds and bats continue to visit fig trees located in sites with high human disturbance, sacred fig trees may promote frugivore abundance. Under favourable microclimate, plenty of seedlings of other tree species would grow around fig trees.
On the basis of the passage given above, the following assumptions have been made :
- 1. Fig trees can often be keystone species in natural forests.
- 2. Fig trees can grow where other large woody species cannot grow.
- 3. Sacred trees can have a role in biodiversity conservation.
- 4. Fig trees have a role in the seed dispersal of other tree species.
Which of the above assumptions is/are valid ?
Answer (a) & explanation
Assumptions 1 and 2 are valid (a). Step 1: the passage says figs feed wildlife "when other resources are scarce". A plant that keeps many animals alive is a keystone species (1). Step 2: it says figs grow where other large trees are absent. So they can grow where other woody species cannot (2). Step 3: UPSC's key treats statement 3, sacred trees aiding conservation, as only conditional in the passage. Statement 4, seed dispersal of other trees, is unstated. So options (b), (c) and (d) fail.
Tip: a keystone species is one whose loss would collapse much of its ecosystem. Figs, which fruit all year, are a classic example in Indian forests.
Answer as per the official UPSC answer key.
Read the passage
The resolution of bankruptcy cases of Indian banks under the Insolvency and Bankruptcy Code should help bring non-performing assets (NPA) situation under some control. Despite the slow pace of resolutions by the National Company Law Tribunal, the Code can be helpful in cleaning up bank books in future credit cycles. The recapitalisation of public sector banks too can help increase the capital cushion of banks and induce them to lend more and boost economic activity. But bad debt resolution and recapitalisation are only a part of the solution as they, by themselves, can do very little to rein in reckless lending that has pushed the Indian banking system to its current sorry state. Unless there are systemic reforms that address the problem of unsustainable lending, future credit cycles will continue to stress the banking system.
Which one of the following statements best reflects the most logical, rational and practical suggestion implied by the passage given above ?
Answer (d) & explanation
The suggestion is that Indian banking needs structural reforms as the long-term answer to bad loans (d). Step 1: the passage says bad-debt resolution and recapitalisation are "only a part of the solution". Step 2: it ends: unless there are "systemic reforms" to stop unsustainable lending, future credit cycles will stress banks. That is (d). Step 3: option (a), government monitoring of lending, and option (c), mergers, are specific steps the passage never proposes. Option (b), low interest rates to boost lending, goes against the passage's worry about reckless lending.
Tip: the last line of a passage often carries its suggestion. Here "unless there are systemic reforms" points straight to (d).
Answer as per the official UPSC answer key.
Joseph visits the club on every 5th day, Harsh visits on every 24th day, while Sumit visits on every 9th day. If all three of them met at the club on a Sunday, then on which day will all three of them meet again ?
Answer (b) & explanation
They meet again on a Wednesday (b). Step 1: they meet again after the LCM of 5, 24 and 9. 24 = 2³ × 3 and 9 = 3², so the LCM = 2³ × 3² × 5 = 360 days. Step 2: find the weekday shift: 360 ÷ 7 = 51 weeks and 3 days left over. Step 3: Sunday + 3 days = Wednesday. Option (d), Sunday, ignores the extra days. Options (a) and (c) miscount.
Tip: "every nth day" problems use the LCM. Then divide by 7 and use the remainder to move the weekday forward.
Answer as per the official UPSC answer key.
Read the passage
There are reports that some of the antibiotics sold in the market are fed to poultry and other livestock as growth promoters. Overusing these substances can create superbugs, pathogens that are resistant to multiple drugs and could be passed along humans. Mindful of that, some farming companies have stopped using the drugs to make chickens gain weight faster. Since Denmark banned antibiotic growth promoters in the 1990s, the major pork exporter says it is producing more pigs — and the animals get fewer diseases.
Which one of the following statements best reflects the critical message conveyed by the passage given above ?
Answer (d) & explanation
The critical message is that antibiotics should only be used to treat diseases (d). Step 1: the passage objects to antibiotics used as growth promoters in farm animals. Denmark banned that use, not all use. So antibiotics should be kept for treating illness. That is (d). Step 2: option (c), banning antibiotics on animals completely, would stop treatment of sick animals too. Step 3: options (a) and (b), avoiding animal products or replacing them with plant foods, are not discussed.
Tip: overuse of antibiotics breeds drug-resistant germs (antimicrobial resistance). India's Kerala launched a state action plan against it in 2018. Choose the option matching the passage's exact objection.
Answer as per the official UPSC answer key.
P scored 40 marks more than Q in an examination. If Q scored 10% less marks than P, then how much did Q score ?
Answer (a) & explanation
Q scored 360 (a). Step 1: Q scored 10% less than P. So the gap between them is 10% of P's marks. Step 2: the gap is 40 marks. So 10% of P = 40, which gives P = 400. Step 3: Q = 400 − 40 = 360. Option (c), 400, is P's score, not Q's. Options (b) 380 and (d) 420 come from using Q as the base of the percentage.
Tip: always ask "10% of whom?". Here "less than P" means P is the base. Check: 10% of 400 is 40, and 400 − 40 = 360.
10% less than P, so the base is P, not Q.
Answer as per the official UPSC answer key.
Read the passage
Researchers simulated street lighting on artificial grassland plots containing pea-aphids, sap-sucking insects, at night. These were exposed to two different types of light — a white light similar to newer commercial LED lights and an amber light similar to sodium street lamps. The low intensity amber light was shown to inhibit, rather than induce, flowering in a wild plant of the pea family which is a source of food for the pea-aphids in grasslands. The number of aphids was also significantly suppressed under the light treatment due to the limited amount of food available.
Which one of the following statements best reflects the most critical inference that can be made from the passage given above ?
Answer (b) & explanation
The critical inference is that light pollution can have a lasting harmful effect on an ecosystem (b). Step 1: the passage says night lighting cut flowering in plants, and through the food chain it cut aphid numbers. One change spread to other living things: a knock-on effect on the ecosystem. That is (b). Step 2: option (a) compares low and high intensity light. The passage reports no such comparison. Step 3: option (c) compares white light with other colours; also not reported. Option (d) talks of "proper intensity", which the passage does not discuss.
Tip: in science passages, the inference usually widens the finding one step (here, from plants to the ecosystem). Options adding new comparisons are traps.
Answer as per the official UPSC answer key.
Read the passage
Inequality violates a basic democratic norm : the equal standing of citizens. Equality is a relation that obtains between persons in respect of some fundamental characteristic that they share in common. Equality is, morally speaking, a default principle. Therefore, persons should not be discriminated on grounds such as race, caste, gender, ethnicity, disability, or class. These features of human condition are morally irrelevant. The idea that one should treat persons with respect not only because some of these persons possess some special features or talent, for example skilled cricketers, gifted musicians, or literary giants, but because persons are human beings, is by now part of commonsense morality.
With reference to the above passage, the following assumptions have been made :
- 1. Equality is a prerequisite for people to participate in the multiple transactions of society from a position of confidence.
- 2. Occurrence of inequality is detrimental to the survival of democracy.
- 3. Equal standing of all citizens is an idea that cannot actually be realised even in a democracy.
- 4. Right to equality should be incorporated into our values and day-to-day political vocabulary.
Which of the above assumptions are valid ?
Answer (c) & explanation
Assumptions 1 and 4 are valid (c). Step 1: the passage calls the equal standing of citizens a basic democratic norm. People need it to take part in society with confidence (1). Step 2: it says respecting persons as human beings is now part of "commonsense morality". So equality should be in our values and everyday vocabulary (4). Step 3: assumption 2 talks of the survival of democracy; the passage only says inequality violates a norm. Assumption 3 says equality cannot be realised, which goes against the passage. So options (a), (b) and (d) fail.
Tip: "violates a norm" is not the same as "destroys the system". Do not let an option exaggerate the passage's claim.
Answer as per the official UPSC answer key.
In the series _b_a_ba_b_abab_aab; fill in the six blanks ( _ ) using one of the following given four choices such that the series follows a specific order.
Answer (d) & explanation
The blanks are filled by ababab (d). Step 1: put the letters a, b, a, b, a, b into the six blanks in order. Step 2: the series becomes abbaab abbaab abbaab. Step 3: the block "abbaab" repeats three times, so the series has a clear order. Options (a) bababa, (b) baabba and (c) bbaabb break this repeating pattern.
Tip: in letter-series questions, try each option and look for a block that repeats. The series length (18 here) often hints at the block size (6).
Answer as per the official UPSC answer key.
Read the passage
At the heart of agroecology is the idea that agroecosystems should mimic the biodiversity levels and functioning of natural ecosystems. Such agricultural mimics, like their natural models, can be productive, pest-resistant, nutrient conserving, and resilient to shocks and stresses. In ecosystems there is no ‘waste’, nutrients are recycled indefinitely. Agroecology aims at closing nutrient loops, i.e., returning all nutrients that come out of the soil back to the soil such as through application of farmyard manure. It also harnesses natural processes to control pests and build soil fertility i.e., through intercropping. Agroecological practices include integrating trees with livestock and crops.
Consider the following :
- 1. Cover crops
- 2. Fertigation
- 3. Hydroponics
- 4. Mixed farming
- 5. Polyculture
- 6. Vertical farming
Which of the above farming practices can be compatible with agroecology, as implied by the passage ?
Answer (a) & explanation
Cover crops, mixed farming and polyculture fit agroecology (a). Step 1: agroecology works with natural soil and nutrient cycles. Cover crops return nutrients to the soil (1). Step 2: mixed farming joins crops and livestock, using dung as manure (4). Polyculture, growing many crops together, is intercropping (5). Step 3: fertigation (fertiliser through irrigation), hydroponics (plants in water) and vertical farming (indoor racks) bypass the soil cycle. So options (b), (c) and (d) fail.
Tip: agroecology means farming like an ecosystem. India's natural farming push, under the National Mission on Natural Farming (2024), follows these ideas.
Answer as per the official UPSC answer key.
Read the passage
In India, the objective of macroeconomic policy is to enhance the economic welfare of the people, and any one wing of such macro policy, monetary or fiscal, cannot independently work without active support of another.
Which one of the following statements best reflects the corollary to the passage given above ?
Answer (a) & explanation
The corollary is that the central bank cannot work independently of the government (a). Step 1: the passage says monetary policy and fiscal policy cannot work "without active support of another". Step 2: monetary policy is run by the central bank (the RBI in India). Fiscal policy (taxes and spending) is run by the government. So the RBI cannot work fully on its own. That is (a). Step 3: options (b) close regulation, (c) socialist policies and (d) financial sector reforms all bring in new ideas that the single sentence does not contain.
Tip: a corollary is a direct, small step from the passage. Translate the key terms (monetary = central bank, fiscal = government) and the answer appears.
Answer as per the official UPSC answer key.
The difference between a 2-digit number and the number obtained by interchanging the positions of the digits is 54.
Consider the following statements :
- 1. The sum of the two digits of the number can be determined only if the product of the two digits is known.
- 2. The difference between the two digits of the number can be determined.
Which of the above statements is/are correct ?
Answer (b) & explanation
1. Swapping the two digits of a number always changes it by 9 × (the gap between the digits). Example: 71 − 17 = 54 = 9 × 6.
2. So 54 ÷ 9 = 6: the digits differ by 6. Statement 2 is correct.
3. The number could be 71, 82 or 93, with digit sums 8, 10 and 12. The sum is not fixed.
4. Statement 1 says the sum can be found 'only if' the product is known. Other facts could also fix it, so 'only if' is wrong. Statement 1 is incorrect.
Answer as per the official UPSC answer key.
Read the passage
Policy makers and media have placed the blame for skyrocketing food prices on a variety of factors, including high fuel prices, bad weather in key food producing countries, and the diversion of land to non-food production. Increased emphasis, however, has been placed on a surge in demand for food from the most populous emerging economies. It seems highly probable that mass consumption in these countries could be well poised to create a food crisis.
With reference to the above passage, the following assumptions have been made :
- 1. Oil producing countries are one of the reasons for high food prices.
- 2. If there is a food crisis in the world in the near future, it will be in the emerging economies.
Which of the above assumptions is/are valid ?
Answer (d) & explanation
Neither assumption is valid (d). Step 1: assumption 1 blames oil-producing countries. But the passage blames high fuel prices, not the countries that produce oil. So 1 fails. Step 2: assumption 2 says a food crisis will be in emerging economies. The passage says demand from emerging economies may cause a crisis, but it does not say where it will strike. So 2 fails. Step 3: so options (a), (b) and (c) fail.
Tip: separate cause from location. "Emerging economies may create a crisis" is not "the crisis will happen in emerging economies". Small word shifts like this decide many CSAT answers.
Answer as per the official UPSC answer key.
A person P asks one of his three friends X as to how much money he had. X replied, "If Y gives me ₹ 40, then Y will have half of as much as Z, but if Z gives me ₹ 40, then three of us will have equal amount." What is the total amount of money that X, Y and Z have ?
Answer (b) & explanation
The total is ₹ 360 (b). Step 1: use the second condition first. If Z gives X ₹ 40, all three are equal. So X + 40 = Y = Z − 40. Step 2: the first condition: if Y gives X ₹ 40, Y has half of Z. So Y − 40 = Z ÷ 2. Put Y = Z − 40: Z − 80 = Z ÷ 2, so Z = 160. Step 3: then Y = 120 and X = 80. Total = 160 + 120 + 80 = ₹ 360. Options (a), (c) and (d) do not satisfy both conditions.
Tip: start with the condition that gives the simplest link ("all equal"). Then plug the answer options back in to check quickly.
Answer as per the official UPSC answer key.
Read the passage
Approximately 80 percent of all flowering plant species are pollinated by animals, including birds and mammals, but the main pollinators are insects. Pollination is responsible for providing us with a wide variety of food, as well as many plant-derived medicines. At least one-third of the world’s agricultural crops depend upon pollination. Bees are the most dominant taxa when it comes to pollination and they are crucial to more than four hundred crops. Pollination is an essential service that is the result of intricate relationships between plants and animals, and the reduction or loss of either affects the survival of both. Effective pollination requires resources, such as refuges of pristine natural vegetation.
On the basis of the passage given above, the following assumptions have been made :
- 1. Sustainable production of India’s cereal food grains is impossible without the diversity of pollinating animals.
- 2. Monoculture of horticultural crops hampers the survival of insects.
- 3. Pollinators become scarce in cultivated areas devoid of natural vegetation.
- 4. Diversity in insects induces diversity of plants.
Which of the above assumptions is/are valid ?
Answer (d) & explanation
Assumptions 3 and 4 are valid (d). Step 1: the passage says pollination needs "refuges of pristine natural vegetation". So pollinators become scarce in farms with no natural plants (3). Step 2: it says losing one partner affects the other, so the diversity of insects and plants go together (4). Step 3: assumption 1 is about cereal grains, and assumption 2 about monoculture of horticulture crops. Neither is mentioned. Also, most cereals like rice and wheat are wind- or self-pollinated. So options (a), (b) and (c) fail.
Tip: reject any statement whose key term (cereals, monoculture) never appears in the passage. Pick the ones you can trace to a line.
Answer as per the official UPSC answer key.
Read the passage
Aristocratic government ruins itself by limiting too narrowly the circle within which power is confined; oligarchic government ruins itself by the incautious scramble for immediate wealth. But even democracy ruins itself by excess of democracy. Its basic principle is the equal right of all to hold office and determine public policy. This is, at first glance, a delightful arrangement; it becomes disastrous because the people are not properly equipped by education to select the best rulers and the wisest courses. The people have no understanding and only repeat what their rulers are pleased to tell them. Such a democracy is tyranny or autocracy. — Plato
Which one of the following statements best reflects the crux of the passage given above ?
Answer (b) & explanation
The crux is that any form of government tends to decay through an excess of its basic principle (b). Step 1: the passage shows aristocracy ruins itself by keeping power too narrow, oligarchy by greed for wealth, and democracy by "excess of democracy". Each fails by pushing its own principle too far. That is (b). Step 2: option (a), societies trying different governments, is only background. Step 3: option (c) says education ensures a perfect democracy, which overpromises. Option (d) calls government a "necessary evil"; Plato does not argue this.
Tip: when a passage gives several examples of one pattern, the crux is the pattern itself, not any single example.
Answer as per the official UPSC answer key.
Using 2, 2, 3, 3, 3 as digits, how many distinct numbers greater than 30000 can be formed ?
Answer (b) & explanation
Six numbers can be formed (b). Step 1: all numbers use all five digits, so they are 5-digit numbers. To be above 30000, the first digit must be 3. Step 2: the remaining digits are 2, 2, 3, 3. The number of ways to arrange them is 4! ÷ (2! × 2!) = 6. Step 3: they are 2233, 2323, 2332, 3223, 3232 and 3322. Options (a), (c) and (d) miscount by ignoring or double-counting the repeated digits.
Tip: when digits repeat, divide by the factorial of each repeat count. Without this, you would count the same number many times.
Answer as per the official UPSC answer key.
Read the passage
Computers increasingly deal not just with abstract data like credit card details and databases, but also with the real world of physical objects and vulnerable human bodies. A modern car is a computer on wheels; an aeroplane is a computer on wings. The arrival of the “Internet of Things” will see computers baked into everything from road signs and MRI scanners to prosthetics and insulin pumps. There is little evidence that these gadgets will be any more trustworthy than their desktop counterparts. Hackers have already proved that they can take remote control of internet connected cars and pacemakers.
Which one of the following statements best reflects the most critical inference that can be made from the passage given above ?
Answer (a) & explanation
The critical inference is that computers are not completely safe (a). Step 1: the passage says hackers have taken control of connected cars and pacemakers. If such devices can be hacked, computers are not fully safe. That is (a). Step 2: option (b) blames companies for not taking security seriously; the passage does not say this. Option (c) asks for new laws; this also goes beyond the passage. Step 3: option (d), technology will affect our lives, is too vague to be the critical inference.
Tip: the safest inference stays closest to the facts given. Blame and remedies usually go beyond a passage that only reports events.
Answer as per the official UPSC answer key.
Consider the following Table :
| Player | Runs scored in the First Innings | Balls faced in the First Innings | Runs scored in the Second Innings | Balls faced in the Second Innings |
|---|---|---|---|---|
| A | 61 | 99 | 14 | 76 |
| B | 05 | 12 | 50 | 85 |
| C | 15 | 75 | 20 | 50 |
| D | 13 | 55 | 12 | 50 |
Who is the fastest run scorer in the Test Match ?
Answer (b) & explanation
B is the fastest scorer (b). Step 1: "fastest" means the most runs per ball over the whole match, not in one innings. So add both innings for each player. Step 2: A scored 75 in 175 balls, about 0.43 runs per ball. B scored 55 in 97 balls, about 0.57. Step 3: C scored 35 in 125 balls (0.28) and D scored 25 in 105 balls (0.24). B has the highest rate, so (b). Option (a), A, has the most runs, but took many more balls.
Tip: speed means a rate, not a total. Divide runs by balls; in cricket, strike rate = runs per 100 balls.
A's first innings looks the most striking, but you have to add both innings before you compare.
Answer as per the official UPSC answer key.