UPSC Prelims PYQs with explanations
Real questions from official papers, mapped to syllabus topics. Attempt each one; the answer and the reason appear instantly.
Consider the following fruits :
- I. Papaya
- II. Pineapple
- III. Guava
How many of the above were introduced in India by the Portuguese in the sixteenth and seventeenth centuries?
Answer (c) & explanation
All three fruits came with the Portuguese (c). The Portuguese brought many New World crops to India in the 16th and 17th centuries. Item I is right: papaya came from Central America. Item II is right: pineapple came from South America. Item III is right: guava came from tropical America. All three came through the Columbian exchange, the swap of plants and animals after 1492. So options (a), (b) and (d) fail.
Notice the other Portuguese imports: tobacco, chilli, potato, tomato, cashew, maize and groundnut. Today India is the largest producer of papaya and guava. Allahabad (Prayagraj) guava is famous, and Meghalaya and Tripura grow sweet pineapples.
Answer as per the official UPSC answer key.
Read the passage
Maintaining an ecosystem just to conserve biodiversity will affect its commercial potential as well as the livelihoods dependent on the ecosystem. There is also a conflict between using an ecosystem only for livelihoods, for commercial exploitation, or strictly for conservation. Deforestation caused due to commercial exploitation will lead to indirect harm like floods, siltation problems and microclimatic instability, apart from adversely affecting livelihoods dependent on forests. These conflicts are particularly acute in developing countries where the dependence of people on the ecosystem is significant, and commercial exploitation has the potential to boost national income.
With reference to above passage, the following assumptions have been made:
- I. No country needs to depend on ecosystems to boost national income.
- II. Resource-rich countries need to share their resources with those of scant resources so as to prevent the degradation of ecosystems.
Which of the above assumptions is/are valid?
Answer (d) & explanation
Neither assumption is valid (d). Step 1: assumption I says no country needs ecosystems to boost national income. But the passage says commercial exploitation "has the potential to boost national income" in developing countries. So I contradicts the passage. Step 2: assumption II asks rich countries to share resources with poor ones. The passage never talks about sharing between countries. Step 3: so I goes against the text and II is outside it. Options (a), (b) and (c) fail.
Tip: an assumption that contradicts a line in the passage is invalid at once. One that brings in a new idea (like international sharing) is also invalid. Check each against the text, not against what sounds fair.
Answer as per the official UPSC answer key.
Read the passage
If there is inequality in the pattern of population growth, there is greater inequality in food production and utilization. As societies become wealthier, their consumption of animal products increases. This means that a greater proportion of such basic foodstuff as grains and legumes that could feed humans directly is instead being converted into feed for poultry and large farm animals. Yet this conversion of plant-based food into animal food for humans is far from efficient. Only 16% of the calories fed to chickens are recovered by us when we eat them. This conversion rate goes down to five to seven per cent in large animals that are fed grain to add fat and some protein before slaughter.
With reference to the above passage, the following assumptions have been made:
- I. The food manufacturing and processing industries in every country should align their objectives and processes in accordance with the changing needs of the societies.
- II. Wealthier societies tend to incur great loss of calories of food materials due to indirect utilization of their agricultural produce.
Which of the above assumptions is/are valid?
Answer (b) & explanation
Only assumption II is valid (b). Step 1: the passage says wealthier societies feed grain to animals and recover only 16% (chicken) or 5–7% (large animals) of the calories. So they lose many calories through this indirect use of farm produce (II). Step 2: assumption I talks about food manufacturing and processing industries aligning with society's needs. The passage does not discuss these industries at all. Step 3: so I is outside the passage. Options (a), (c) and (d) fail.
Tip: when an assumption names a group (industries, governments) that the passage never mentions, reject it. Feeding animals grain is why meat has a bigger land and water footprint than plant food.
Answer as per the official UPSC answer key.
In a certain code if 64 is written as 343 and 216 is written as 729, then how is 512 written in that code?
Answer (b) & explanation
512 is written as 1331 (b). Step 1: notice the cubes: 64 = 4³ and 343 = 7³. 216 = 6³ and 729 = 9³. Step 2: the rule: add 3 to the cube root, then cube again: 4 → 7, 6 → 9. Step 3: 512 = 8³, so 8 + 3 = 11, and 11³ = 1331. Option (a), 1000 = 10³, adds only 2. Options (c) 12³ and (d) 13³ add too much.
Tip: learn cubes up to 15 (1331 = 11³, 1728 = 12³, 2197 = 13³). Spotting squares and cubes solves many number codes quickly.
Answer as per the official UPSC answer key.
Consider the following statements in respect of the Non-Cooperation Movement :
- I. The Congress declared the attainment of ‘Swaraj’ by all legitimate and peaceful means to be its objective.
- II. It was to be implemented in stages with civil disobedience and non-payment of taxes for the next stage only if ‘Swaraj’ did not come within a year and the Government resorted to repression.
Which of the statements given above is/are correct?
Answer (c) & explanation
Both statements are correct (c). Statement I is right: at Nagpur (December 1920), the Congress changed its goal from self-government within the Empire to Swaraj by "all legitimate and peaceful means". Statement II is right: Gandhi's plan went in stages. Boycotts came first, then civil disobedience and non-payment of taxes if Swaraj did not come within a year and the government turned to repression. So options (a), (b) and (d) fail.
Notice the context: anger over the Rowlatt Act, Jallianwala Bagh (1919) and the Khilafat issue brought Hindus and Muslims together. The Calcutta special session (September 1920) first approved the programme. The Bardoli no-tax campaign was planned, then dropped after Chauri Chaura.
Answer as per the official UPSC answer key.
Consider the following pairs :
| State | Description
| I. Arunachal Pradesh | The capital is named after a fort, and the State has two National Parks
| II. Nagaland | The State came into existence on the basis of a Constitutional Amendment Act
| III. Tripura | Initially a Part 'C' State, it became a centrally administered territory with the reorganization of States in 1956 and later attained the status of a full-fledged State
How many of the above pairs are correctly matched?
Answer (c) & explanation
All three pairs are treated as correctly matched (c). Pair I is right: Itanagar takes its name from the Ita Fort, and Arunachal has two national parks, Namdapha and Mouling. Pair II is right: Nagaland was created in 1963 by the State of Nagaland Act, 1962, together with the 13th Amendment (1962), which added Article 371A. Pair III is right: Tripura went from a Part C State to a Union Territory in 1956, and became a full State in 1972. So options (a), (b) and (d) fail.
Notice that Manipur and Meghalaya also became States in 1972, under the North-Eastern Areas (Reorganisation) Act, 1971. Arunachal and Mizoram became States in 1987. Article 371A protects Naga customary law and land.
three different kinds of fact in one question: a name, a law, a change of status. Check each pair on its own.
Answer as per the official UPSC answer key.
Consider the following statements with regard to pardoning power of the President of India :
- I. The exercise of this power by the President can be subjected to limited judicial review.
- II. The President can exercise this power without the advice of the Central Government.
Which of the statements given above is/are correct?
Answer (a) & explanation
Only statement I is correct (a). Statement I is right: the Supreme Court has held that a pardon under Article 72 can be reviewed on narrow grounds, such as bad faith, irrelevant reasons or arbitrariness (Epuru Sudhakar, 2006). Statement II is wrong: the Court has held that the President acts on the advice of the Council of Ministers here, as elsewhere (Maru Ram, 1980). So options (b), (c) and (d) fail.
Notice the forms of mercy: pardon (wipes out the sentence), commutation (lighter form), remission (shorter term), respite (lighter due to special facts) and reprieve (stay). Only the President can pardon a death sentence or court-martial sentence; Governors' powers under Article 161 are narrower.
the pardon feels like a personal power of the President. It is exercised on ministerial advice.
Answer as per the official UPSC answer key.
Read the passage
If the social inequality is the most acutely felt social problem in India, insecurity, more than poverty, is the most acutely felt economic problem. Besides those below the official poverty line, even those just over the poverty line are subject to multiple economic insecurities of various kinds (due to wealth and/or health risks, market fluctuations, job-related uncertainties). Many Government policies are actually intended towards mitigating these insecurities.
Which one of the following statements best reflects the critical message conveyed by the passage?
Answer (d) & explanation
The critical message is that insecurity, more than poverty, is the main economic issue policy must address (d). Step 1: the passage says plainly: "insecurity, more than poverty, is the most acutely felt economic problem." Step 2: it adds that even those just above the poverty line face risks from health, markets and jobs, and many policies aim at "mitigating these insecurities". That is (d). Step 3: option (a) calls insecurity a social problem; the passage calls inequality the social problem. Option (b) makes poverty the primary cause. Option (c) calls it "unmanageable", which is not stated.
Tip: watch for options that mix up labels (social vs economic). Social security schemes like health insurance and pensions target such insecurity.
Answer as per the official UPSC answer key.
A set (X) of 20 pipes can fill 70% of a tank in 14 minutes. Another set (Y) of 10 pipes fills 3/8th of the tank in 6 minutes. A third set (Z) of 16 pipes can empty half of the tank in 20 minutes. If half of the pipes of set X are closed and only half of the pipes of set Y are open, and all pipes of the set (Z) are open, then how long will it take to fill 50% of the tank?
Answer (d) & explanation
It takes 16 minutes to fill half the tank (d). Step 1: work out the rate of each full set per minute. X fills 70% in 14 min: 5% a minute; half of X = 2.5%. Y fills 37.5% in 6 min: 6.25%; half of Y = 3.125%. Z empties 50% in 20 min: 2.5% a minute (all of Z is open). Step 2: net filling = 2.5 + 3.125 − 2.5 = 3.125% a minute. Step 3: time for 50% = 50 ÷ 3.125 = 16 minutes. Options (a), (b) and (c) forget to halve a set or ignore the emptying pipes.
Tip: convert everything into "percent of tank per minute". Add filling pipes, subtract emptying ones, then divide.
Answer as per the official UPSC answer key.
Consider a set of 11 numbers :
Value-I = Minimum value of the average of the numbers of the set when they are consecutive integers ≥ −5.
Value-II = Minimum value of the product of the numbers of the set when they are consecutive non-negative integers.
Which one of the following is correct?
Answer (c) & explanation
The two values are equal (c). Step 1: Value-I: eleven consecutive integers, all at least −5. To make the average smallest, start as low as allowed: −5 to 5. These cancel in pairs, so the average is 0. Step 2: Value-II: eleven consecutive non-negative integers. Start at 0: 0, 1, …, 10. Anything times 0 is 0, so the product is 0, the smallest possible. Step 3: both values are 0, so they are equal. Options (a), (b) and (d) fail.
Tip: for consecutive numbers, the average is the middle term (here 0). Any set that includes 0 has product 0.
Answer as per the official UPSC answer key.
Consider the following statements :
- Statement I : Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions.
- Statement II : Silica-bearing clay is mixed with limestone while manufacturing cement.
- Statement III : Limestone is converted into lime during clinker production for cement manufacturing.
Which one of the following is correct in respect of the above statements?
Answer (b) & explanation
Both II and III are correct, but only III explains I (b). Statement I is right: cement gives about 7–8% of the world's CO₂. Statement II is right: silica-bearing clay is mixed with limestone to make cement, but that step releases no carbon. Statement III is right and is the reason: heating limestone (CaCO₃) in a kiln gives lime (CaO) and CO₂. This calcination step, plus the fuel burnt for the high heat, causes most of the emissions. So options (a), (c) and (d) fail.
Notice the fixes: blending in fly ash or slag, LC3 (limestone calcined clay cement), and carbon capture. India is the world's second-largest cement producer after China, and its carbon market covers cement.
Answer as per the official UPSC answer key.
A country's fiscal deficit stands at ₹50,000 crores. It is receiving ₹10,000 crores through non-debt creating capital receipts. The country's interest liabilities are ₹1,500 crores. What is the gross primary deficit?
Answer (a) & explanation
The gross primary deficit is ₹48,500 crore (a). Gross primary deficit = gross fiscal deficit − interest payments = 50,000 − 1,500 = ₹48,500 crore. Non-debt capital receipts are already counted inside the fiscal deficit, so they play no further part. That figure is there only to tempt you into adding or subtracting it. Option (b), ₹51,500 crore, wrongly adds interest. Option (c), ₹58,500 crore, wrongly brings in the non-debt receipts. Option (d) fails because (a) is right.
Notice what each deficit tells you: fiscal deficit shows total borrowing need; primary deficit removes the burden of past debt; revenue deficit shows borrowing to meet day-to-day spending. A primary surplus means today's spending is covered without new debt, apart from interest.
the ₹10,000 crore figure. Subtract it and you get a wrong answer; add it and you land on (c).
Answer as per the official UPSC answer key.
Consider the following statements with regard to BRICS :
- I. 16th BRICS Summit was held under the Chairship of Russia in Kazan.
- II. Indonesia has become a full member of BRICS.
- III. The theme of the 16th BRICS Summit was Strengthening Multiculturalism for Just Global Development and Security.
Which of the statements given above is/are correct?
Answer (a) & explanation
Statements I and II are correct (a). Statement I is right: Russia hosted the 16th BRICS summit at Kazan in October 2024. Statement II is right: Indonesia became a full member in January 2025. Statement III is wrong: the theme was "Strengthening Multilateralism for Just Global Development and Security", not multiculturalism. So options (b), (c) and (d) fail.
Notice the expansion: Egypt, Ethiopia, Iran and the UAE joined in 2024; Kazan also created a "partner country" tier. Brazil hosted the 17th summit in Rio (2025), and India chairs BRICS in 2026. The BRICS New Development Bank is based in Shanghai.
One word, multiculturalism for multilateralism, is the whole trap in statement III.
Answer as per the official UPSC answer key.
Read the passage
In our country, handlooms are equated with a culture that ensures a continuity of tradition. This idea has become part of the public policy-framing and provides a legitimate basis for the State to support the sector. But the notion of tradition as a single, linear entity is being strongly contested today. The narratives dominant in defining culture/tradition in a particular way are seen to have emerged as the identities and histories of large sections. The discounted and, at times, forcibly stifled identities are fighting for their rightful place in history. Against this backdrop, when we promote handloom as a traditional industry, it is not surprising that large sections of our population choose to ignore it.
With reference to the above passage, the following assumptions have been made:
- I. There is no need for the State to be involved in any manner in the handloom sector.
- II. Handloom products are no longer appealing and attractive in the rapidly changing modern world.
Which of the above assumptions is/are valid?
Answer (d) & explanation
Neither assumption is valid (d). Step 1: assumption I says the State should have no role at all. The author only questions how the State frames its support (as tradition), not support itself. So I fails. Step 2: assumption II says handloom products are no longer appealing. The passage says people ignore the narrative, the "traditional" label, not the products. So II fails too. Step 3: options (a), (b) and (c) fail.
Tip: separate the product from the way it is presented. Criticising a policy's framing is not rejecting the policy. Extreme words like "no need ... in any manner" are usually wrong.
Answer as per the official UPSC answer key.
If NO is coded as 210, NOT is coded as 4200 and NOTE is coded as 21000, then how is NOTES coded?
Answer (a) & explanation
NOTES is coded as 399000 (a). Step 1: use alphabet positions: N = 14, O = 15. 14 × 15 = 210 = NO ✓. Step 2: T = 20: 210 × 20 = 4200 = NOT ✓. E = 5: 4200 × 5 = 21000 = NOTE ✓. The rule is the product of positions. Step 3: S = 19: 21000 × 19 = 399000. Options (b), (c) and (d) multiply by 20, 21 or 30 instead of 19.
Tip: when each longer word's code is a multiple of the shorter one's, the rule is likely multiplication by the new letter's position. Know positions by heart: N = 14, S = 19.
Answer as per the official UPSC answer key.
Consider the following statements :
- I. India accounts for a very large portion of all equity option contracts traded globally thus exhibiting a great boom.
- II. India's stock market has grown rapidly in the recent past even overtaking Hong Kong's at some point of time.
- III. There is no regulatory body either to warn the small investors about the risks of options trading or to act on unregistered financial advisors in this regard.
Which of the statements given above are correct?
Answer (a) & explanation
Statements I and II are correct (a). Statement I is right: by 2024, India's NSE accounted for most of the equity options contracts traded in the world, a huge boom. Statement II is right: in January 2024, India's stock market value passed Hong Kong's to become the fourth largest. Statement III is wrong: SEBI regulates the market. It warned that about 9 out of 10 small traders in futures and options lose money, and it acts against unregistered advisers and "finfluencers".
Notice the later steps: SEBI tightened F&O rules from late 2024, with bigger contract sizes and fewer weekly expiries, to cool this speculation. Options let you bet on price moves with a small upfront cost, which is why so many lose.
Answer as per the official UPSC answer key.
With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements :
- I. All types of UAVs can do vertical landing.
- II. All types of UAVs can do automated hovering.
- III. All types of UAVs can use battery only as a source of power supply.
How many of the statements given above are correct?
Answer (d) & explanation
None of the statements is correct (d). Each statement says "all types", which is the trap. Statement I is wrong: multi-rotor drones land vertically, but fixed-wing UAVs, such as most military drones, need a runway or a net. Statement II is wrong: fixed-wing UAVs cannot hover; they must keep moving forward. Statement III is wrong: large UAVs run on fuel engines, and some use solar power or hydrogen. So options (a), (b) and (c) fail.
Notice India's drone push: the Drone Rules, 2021, the PLI scheme for drones, and Namo Drone Didi, giving drones to women's self-help groups for spraying crops. India is buying US MQ-9B drones, and drones were widely used in Operation Sindoor (2025).
"All types" in every statement is the clue. One counter-example, the fixed-wing drone, breaks all three.
Answer as per the official UPSC answer key.
Consider the following countries :
- I. United Kingdom
- II. Denmark
- III. New Zealand
- IV. Australia
- V. Brazil
How many of the above countries have more than four time zones?
Answer (b) & explanation
Four of the five have more than four time zones (b). Overseas territories add time zones. Item I is right: the UK has nine, with places like the Falklands and Pitcairn. Item IV is right: Australia has nine with its territories. Item II is right: Denmark has five with Greenland and the Faroes. Item III is right: New Zealand has five with the Chatham Islands, Tokelau, the Cook Islands and Niue. Item V is wrong: Brazil has four, so it does not qualify.
Notice the record holder: France has the most time zones, 12, thanks to territories across the world. Russia has 11 on its mainland. India uses one zone, IST, set at 82.5°E near Mirzapur, five and a half hours ahead of GMT.
Count the islands and territories, not only the mainland. Mainland Denmark has a single zone.
Answer as per the official UPSC answer key.
Read the passage
The history of renewable energy suggests there is a steep learning curve, meaning that, as more is produced, costs fall rapidly because of economies of scale and learning by doing. The firms’ green innovation is path-dependent: the more a firm does, the more it is likely to do in the future. The strongest evidence for this is the collapse in the price of solar energy, which became about 90% cheaper during the 2010s, repeatedly beating forecasts. Moving early and gradually gives economies more time to adjust, allowing them to reap the benefits of path-dependent green investment without much disruption. A late, more chaotic transition is costlier.
Which one of the following statements best reflects the central idea of the passage?
Answer (d) & explanation
The central idea is that timing matters greatly in green technology (d). Step 1: the passage explains a learning curve: the more is produced, the faster costs fall, as with solar, which became about 90% cheaper in the 2010s. Step 2: its conclusion: "Moving early and gradually" helps economies adjust, while "a late, more chaotic transition is costlier." That is about timing: (d). Step 3: option (a), economies of scale, and (b), path-dependent innovation, are supporting points, not the main idea. Option (c), large economies, is never mentioned.
Tip: the conclusion of a passage usually gives its central idea; earlier lines are evidence. Ask: what is the author finally recommending?
Answer as per the official UPSC answer key.
What is the maximum value of n such that 7 × 343 × 385 × 1000 × 2401 × 77777 is divisible by 35n?
Answer (b) & explanation
The maximum n is 4 (b). Step 1: 35ⁿ = 5ⁿ × 7ⁿ. So we need to count both the 5s and the 7s and take the smaller count. Step 2: 7s are plentiful: 7, 343 = 7³, 2401 = 7⁴, 385 and 77777 = 7 × 11111 all add 7s. So count the 5s. Step 3: 385 = 5 × 7 × 11 gives one 5; 1000 = 2³ × 5³ gives three. The others have none. Total 5s = 4, so n = 4. Options (a), (c) and (d) miscount.
Tip: for the highest power of a composite number, split it into primes and count the scarcer prime. Here 5 is the limiting factor.
Answer as per the official UPSC answer key.