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
An air quality index (AQI) is a way to combine measurements of multiple air pollutants into a single number or rating. This index is ideally kept constantly updated and available in different places. The AQI is most useful when lots of pollution data are being gathered and when pollution levels are normally, but not always, low. In such cases, if pollution levels spike for a few days, the public can quickly take preventive action (like staying indoors) in response to an air quality warning. Unfortunately, that is not urban India. Pollution levels in many large Indian cities are so high that they remain well above any health or regulatory standard for large part of the year. If our index stays in the ‘Red/Dangerous’ region day after day, there is not much any one can do, other than getting used to ignoring it.
Which among the following is the most logical and rational inference that can be made from the above passage?
Answer (c) & explanation
The inference is that the air quality index is not helpful to residents of many large cities (c). Step 1: the passage says an index stuck in 'Red' leaves residents nothing to do "other than getting used to ignoring it". So the index is not helping them. That is option (c). Step 2: option (b) says there is absolutely no need for indices anywhere. That goes beyond the large-city point. Step 3: option (a) blames governments, which the passage does not do. Option (d), more awareness in every city, is not the point.
Tip: India's AQI has six bands, from Good to Severe. The passage's point is that a warning that never changes stops being useful.
Answer as per the official UPSC answer key.
Read the passage
There is no harm in cultivating habits so long as they are not injurious. Indeed, most of us are little more than bundle of habits. Take away our habits and the residuum would hardly be worth bothering about. We could not get on without them. They simplify the mechanism of life. They enable us to do a multitude of things automatically, which, if we had to give fresh and original thought to them each time, would make existence an impossible confusion.
The author suggests that habits
Answer (c) & explanation
The author suggests that habits make it easier for us to live (c). Step 1: the passage says habits "simplify the mechanism of life" and save us from "an impossible confusion". So habits make daily life easier. That is option (c). Step 2: option (a), that habits make life difficult, is the opposite. Step 3: option (d) says habits mechanise our lives. The passage says habits work "automatically", but it means they free us, not that they make us machines. Option (b), adding precision, is not the author's point.
Tip: do not confuse a word in the passage, like "mechanism", with the option built from it. Match the meaning, not just the word.
Answer as per the official UPSC answer key.
In a test, Randhir obtained more marks than the total marks obtained by Kunal and Debu. The total marks obtained by Kunal and Shankar are more than those of Randhir. Sonal obtained more marks than Shankar. Neha obtained more marks than Randhir. Who amongst them obtained highest marks?
Answer (d) & explanation
The data are inadequate (d). Step 1: Randhir scored more than Kunal and Debu combined. Neha scored more than Randhir. Step 2: Sonal scored more than Shankar. Kunal and Shankar together beat Randhir. Step 3: nothing compares Neha with Sonal. Neha beats Randhir, and Sonal beats Shankar, but Sonal could be above or below Neha. So the top scorer cannot be found. Option (a), Randhir, is beaten by Neha. Options (b) Neha and (c) Sonal are both possible but not certain.
Tip: before naming a "highest", make sure one person is linked above everyone. Two separate chains with no link between their tops mean the data are not enough.
Answer as per the official UPSC answer key.
In a school, there are five teachers A, B, C, D and E. A and B teach Hindi and English. C and B teach English and Geography. D and A teach Mathematics and Hindi. E and B teach History and French. Who teaches maximum number of subjects?
Answer (b) & explanation
B teaches the most subjects (b). Step 1: list each teacher's subjects. B appears in three pairs: Hindi and English (with A), English and Geography (with C), and History and French (with E). Step 2: so B teaches Hindi, English, Geography, History and French. That is 5 subjects. Step 3: A teaches Hindi, English and Mathematics, which is 3. D teaches Mathematics and Hindi, which is 2. E teaches History and French, which is 2. C teaches English and Geography. So option (b) is right.
Tip: write each name once and list all the subjects linked to it, without repeats. The person who appears in the most pairs usually has the most subjects.
Answer as per the official UPSC answer key.
Consider the following :
A + B means A is the son of B.
A − B means A is the wife of B.
What does the expression P + R − Q mean?
Answer (c) & explanation
Q is P's father (c). Step 1: "A + B" means A is the son of B. So P + R means P is the son of R. Step 2: "A − B" means A is the wife of B. So R − Q means R is the wife of Q. Step 3: R is P's mother, and Q is R's husband. So Q is P's father. Option (a), Q is P's son, reverses the relation. Option (b), Q is P's wife, is wrong because Q is R's husband. Option (d) fails because (c) is clear.
Tip: decode coded relations one pair at a time, left to right. Draw a small family tree as you go; it makes the final link easy to read.
Answer as per the official UPSC answer key.
How many numbers are there between 99 and 1000 such that the digit 8 occupies the units place?
Answer (c) & explanation
There are 90 such numbers (c). Step 1: numbers between 99 and 1000 are the three-digit numbers, 100 to 999. Step 2: the units digit is fixed as 8. The hundreds digit can be 1 to 9, which is 9 ways. The tens digit can be 0 to 9, which is 10 ways. Step 3: total = 9 × 10 = 90. These are 108, 118, … up to 998. Option (b), 80, wrongly leaves out tens digit 0 or 8. Option (a), 64, and option (d), 104, do not fit.
Tip: in digit-counting questions, fill each place separately and multiply the choices. Remember the first digit cannot be 0, but other places can.
Answer as per the official UPSC answer key.
P = (40% of A) + (65% of B) and Q = (50% of A) + (50% of B), where A is greater than B. In this context, which of the following statements is correct?
Answer (d) & explanation
Nothing can be concluded with certainty (d). Step 1: P − Q = (0.40A + 0.65B) − (0.50A + 0.50B) = 0.15B − 0.10A. Step 2: the sign depends on how much bigger A is than B. If A = 1.2B, then 0.15B − 0.12B is positive, so P > Q. Step 3: if A = 2B, then 0.15B − 0.20B is negative, so P < Q. If A = 1.5B, P = Q. So options (a), (b) and (c) are each possible but not certain.
Tip: when an answer depends on values you are not given, test two very different cases. If they give different results, choose "cannot be concluded".
Answer as per the official UPSC answer key.
Read the passage
Productive jobs are vital for growth and a good job is the best form of inclusion. More than half of our population depends on agriculture, but the experience of other countries suggests that the number of people dependent on agriculture will have to shrink if per capita incomes in agriculture are to go up substantially. While industry is creating jobs, too many such jobs are low-productivity non-contractual jobs in the unorganized sector, offering low incomes, little protection, and no benefits. Service jobs are relatively of high productivity, but employment growth in services has been slow in recent years.
Which among the following is the most logical and rational inference that can be made from the above passage?
Answer (c) & explanation
We must create productive jobs outside agriculture while also raising farm productivity (c). Step 1: the passage says fewer people must depend on farming for farm incomes to rise. Industry and services both need productive jobs. So we need jobs outside farming and better farming. That is option (c). Step 2: option (a) covers services only, and leaves out industry. Step 3: option (b) says simply shift farm workers, ignoring farm productivity. Option (d) brings in hybrid and GM crops, which the passage does not discuss.
Tip: in India, close to half of workers are in agriculture, but it produces under a fifth of GDP. That is why moving workers to productive jobs matters.
Answer as per the official UPSC answer key.
Consider the given information and answer the item that follows.
No supporters of 'party X', who knew Z and supported his campaign strategy, agreed for the alliance with 'party Y'; but some of them had friends in 'party Y'.
With reference to the above information, which one among the following statements must be true?
Answer (b) & explanation
Option (b) must be true: at least one supporter of party Y knows some supporter of party X as a friend (b). Step 1: the information says some X supporters, who knew Z and backed his strategy, "had friends in party Y". Step 2: a friendship goes both ways. So at least one Y supporter has an X supporter as a friend. That is option (b). Step 3: options (c) and (d) say no X supporter backed Z's strategy or knew Z. Both contradict the information. Option (a) is about what Y supporters thought of the alliance, which is never given.
Tip: "must be true" needs proof from the facts. Turn the given sentence around; friendship is mutual, so the reverse also holds.
Answer as per the official UPSC answer key.
Read the passage
Disruption of traditional institutions, identifications and loyalties is likely to lead to ambivalent situations. It is possible that some people may renew their identification with traditional groups whereas others align themselves with new groups and symbols emergent from processes of political development. In addition, political development tends to foster group awareness of a variety of class, tribe, region, clan, language, religion, occupation and others.
Which one of the following is the best explanation of the above passage?
Answer (a) & explanation
The best explanation is that political development is not a one-way process; it involves both growth and decay (a). Step 1: the passage says some people renew old loyalties while others join new groups. So change moves in more than one direction. That is option (a). Step 2: option (c) says breaking away from old loyalties is impossible. But some people do join new groups. Step 3: option (b), that traditional societies succeed in resisting good change, is not claimed. Option (d) says old loyalties help development, which the passage does not say.
Tip: "unilinear" means moving in a single straight line. When a passage shows movement both ways, pick the option that says change is mixed.
Answer as per the official UPSC answer key.
A 2-digit number is reversed. The larger of the two numbers is divided by the smaller one. What is the largest possible remainder?
Answer (d) & explanation
The largest possible remainder is 45 (d). Step 1: when the quotient is 1, the remainder is just the difference of the two numbers. That difference is always 9 × (difference of the digits). Step 2: to make the difference large while the quotient stays 1, the bigger number must be less than twice the smaller. Take digits 9 and 4: 94 ÷ 49 = 1, remainder 45. Step 3: try 95 and 59: 95 ÷ 59 = 1, remainder 36. Bigger digit gaps make the quotient 2 or more and the remainder smaller. Options (a), (b) and (c) are possible remainders but not the largest.
Tip: test the highest option first. If it works and nothing beats it, you are done.
Answer as per the official UPSC answer key.
Gopal bought a cell phone and sold it to Ram at 10% profit. Then Ram wanted to sell it back to Gopal at 10% loss. What will be Gopal's position if he agreed?
Answer (c) & explanation
Gopal gains 1% (c). Step 1: suppose Gopal first paid Rs 100 for the phone. He sold it to Ram at 10% profit, for Rs 110. Step 2: Ram sells it back at 10% loss on his own price. 10% of 110 = 11, so the price is Rs 99. Step 3: Gopal now has the same phone for Rs 99 instead of Rs 100. That is Rs 1 less on every Rs 100 he first spent. That is a gain of 1%. Option (a), no loss no gain, is the trap of thinking 10% up and 10% down cancel. Options (b) and (d) do not fit.
Tip: percentages up and down use different bases, so they never simply cancel.
Counting all the cash (+110 − 100 − 99), some say Gopal is better off by ₹ 11; the official answer is (c), as printed.
Answer as per the official UPSC answer key.
If for a sample data Mean < Median < Mode then the distribution is
Answer (d) & explanation
The distribution is skewed to the left (d). Step 1: in a balanced, symmetric set, the mean, median and mode are all equal. So option (a) is out. Step 2: a few very small values pull the mean down the most, then the median a little. The mode stays at the peak. Step 3: so Mean < Median < Mode means a long tail on the small, left side. That is left skew, also called negative skew. Option (b), skewed to the right, would give Mean > Median > Mode. Option (c) is not a real category here.
Tip: the mean always moves towards the long tail. If the mean is the smallest of the three, the tail is on the left.
Answer as per the official UPSC answer key.
A watch loses 2 minutes in every 24 hours while another watch gains 2 minutes in every 24 hours. At a particular instant, the two watches showed an identical time. Which of the following statements is correct if 24-hour clock is followed?
Answer (d) & explanation
None of the statements is correct (d). Step 1: one watch loses 2 minutes a day and the other gains 2 minutes a day. So they drift apart by 4 minutes a day. Step 2: on a 24-hour clock, they show the same time again only when the gap is a full 24 hours, which is 1440 minutes. Step 3: days needed = 1440 ÷ 4 = 360 days. This is not 30, 90 or 120. So options (a), (b) and (c) are wrong. Option (b), 90 days, would be the answer only for a 6-hour gap.
Tip: on a 12-hour clock the full gap is 720 minutes; on a 24-hour clock it is 1440. Read which clock the question uses.
on a 12-hour dial the answer would be 180 days. The question says 24-hour clock, and none of the options fit either way.
Answer as per the official UPSC answer key.
Read the passage
A landscape-scale approach to land use can encourage greater biodiversity outside protected areas. During hurricane ‘Mitch’ in 1998, farms using ecoagricultural practices suffered 58 per cent, 70 per cent and 99 per cent less damage in Honduras, Nicaragua and Guatemala, respectively, than farms using conventional techniques. In Costa Rica, vegetative windbreaks and fencerows boosted farmers’ income from pasture and coffee while also increasing bird diversity. Bee pollination is more effective when agricultural fields are closer to natural or seminatural habitat, a finding that matters because 87 per cent of the world’s 107 leading crops depend on animal pollinators. In Costa Rica, Nicaragua and Colombia silvopastoral systems that integrate trees with pastureland are improving the sustainability of cattle production, and diversifying and increasing farmers’ income.
Which among the following is the most logical and rational inference that can be made from the above passage?
Answer (a) & explanation
Farming that boosts biodiversity can often raise output and reduce disaster risk (a). Step 1: the passage says ecofarms suffered far less hurricane damage, and windbreaks and pollinators raised income. So such practices help output and resilience. That is option (a). Step 2: option (b) says replace ecoagriculture with conventional farming. That reverses the lesson. Step 3: option (c) is about protected areas, but the approach works outside them, so (c) misreads it. Option (d) says yields will be very high, which is overstated.
Tip: ecoagriculture means farming that also protects nature, like agroforestry. Watch for options that flip the passage's lesson.
Answer as per the official UPSC answer key.
(Same information as the question above.)
With reference to the above information, consider the following statements :
- 1. Some supporters of 'party X' knew Z.
- 2. Some supporters of 'party X', who opposed Z's campaign strategy, knew Z.
- 3. No supporters of 'party X' supported Z's campaign strategy.
Which of the statements given above is/are not correct?
Answer (c) & explanation
Only statement 3 is not correct (c). Step 1: the information talks about X supporters who knew Z and supported his strategy. So some X supporters knew Z, and statement 1 is correct. Step 2: statement 3 says no X supporter backed Z's strategy. That plainly contradicts the information, so 3 is not correct. Step 3: statement 2 is about other X supporters, who opposed Z's strategy but knew him. The information neither confirms nor denies this. So it cannot be called wrong. Options (a), (b) and (d) fail.
Tip: "not correct" means proven false. A statement the facts do not mention is "unknown", not "incorrect". Keep these three groups apart: true, false and unknown.
Answer as per the official UPSC answer key.
Read the passage
There has been a significant trend worldwide towards regionalism in government, resulting in a widespread transfer of powers downwards towards regions and communities since 1990s. This process, which involves the creation of new political entities and bodies at a sub-national level and an increase in their content and powers, is known as devolution. Devolution has been characterized as being made up of three factors—political legitimacy, decentralization of authority and decentralization of resources. Political legitimacy here means a mass demand from below for the decentralization process, which is able to create a political force for it to take place. In many cases, decentralization is initiated by the upper tier of government without sufficient political mobilization for it at the grassroots level, and in such cases the decentralization process often does not fulfil its objectives.
Which among the following is the most logical, rational and critical inference that can be made from the above passage?
Answer (c) & explanation
Devolution needs democracy with free expression and active participation at the grassroots (c). Step 1: the passage says devolution needs "a mass demand from below". It adds that decentralisation imposed from the top "often does not fulfil its objectives". So people's will and participation at lower levels are key. That is option (c). Step 2: option (b), imposing devolution from the top, is exactly what the passage says fails. Step 3: option (a), powerful mass leaders, is not mentioned. Option (d), strong regionalism, is not required.
Tip: India's 73rd and 74th Amendments set up panchayats and municipalities. They work best where local people actively take part, as the passage suggests.
Answer as per the official UPSC answer key.
The monthly incomes of X and Y are in the ratio of 4 : 3 and their monthly expenses are in the ratio of 3 : 2. However, each saves ₹ 6,000 per month. What is their total monthly income?
Answer (b) & explanation
Their total monthly income is Rs 42,000 (b). Step 1: test the options. Split the total income in the ratio 4 : 3, subtract Rs 6,000 savings from each, and check whether expenses come out as 3 : 2. Step 2: option (b): incomes Rs 24,000 and Rs 18,000. Expenses Rs 18,000 and Rs 12,000. 18 : 12 = 3 : 2. It works. Step 3: option (a), Rs 28,000: incomes 16,000 and 12,000, expenses 10,000 and 6,000 = 5 : 3. It fails. Options (c) and (d) also fail the expense ratio.
Tip: algebra works too: 4x − 6000 : 3x − 6000 = 3 : 2 gives x = 6000. But testing options is often faster in CSAT.
Answer as per the official UPSC answer key.
Read the passage
We have hard work ahead. There is no resting for any of us till we redeem our pledge in full, till we make all the people of India what destiny intends them to be. We are citizens of a great country, on the verge of bold advance, and we have to live up to that high standard. All of us, to whatever religion we may belong, are equally the children of India with equal rights, privileges and obligations. We cannot encourage communalism or narrow-mindedness, for no nation can be great whose people are narrow in thought or action.
The challenge the author of the above passage throws to the public is to achieve
Answer (d) & explanation
The challenge is hard work, brotherhood and national unity (d). Step 1: the passage says "we have hard work ahead", that all are "equally the children of India", and that communalism must be rejected. These are hard work, brotherhood and unity. That is option (d). Step 2: option (a) mentions a high standard of living. But the passage's "high standard" is about conduct, not wealth. Step 3: options (b) and (c), privileges, destiny, adventure and economic parity, pick words that are not the author's challenge.
Tip: match each idea in an option to a phrase in the passage before choosing.
Answer as per the official UPSC answer key.
The age of Mr. X last year was the square of a number and it would be the cube of a number next year. What is the least number of years he must wait for his age to become the cube of a number again?
Answer (b) & explanation
He must wait 38 years (b). Step 1: his age last year was a square, and next year will be a cube. These two ages are 2 years apart. Look for a square and a cube that differ by 2: 25 and 27. Step 2: so last year he was 25, next year he will be 27, and now he is 26. Step 3: the next cube after 27 is 64. He must wait 64 − 26 = 38 years. Option (a), 42, does not fit. Option (c), 25, and option (d), 16, are squares from the puzzle, not the wait.
Tip: learn small squares and cubes by heart: cubes are 1, 8, 27, 64, 125. Checking pairs from such lists solves these puzzles fast.
64 – 27 = 37 counts from next year, not from now.
Answer as per the official UPSC answer key.