UPSC Prelims PYQs with explanations
Real questions from official papers, mapped to syllabus topics. Attempt each one; the answer and the reason appear instantly.
Right to vote and to be elected in India is a
Answer (c) & explanation
UPSC treated the right to vote and to be elected as a constitutional right (c). Article 326 says elections to the Lok Sabha and State Assemblies shall be based on adult suffrage, so every citizen aged 18 and above can vote (the age was lowered from 21 by the 61st Amendment, 1988). Articles 84 and 173 set out who may be elected. Since these are in the Constitution but not in Part III, it is not a Fundamental Right (a), and it is not a natural right (b).
The Supreme Court has also called voting a statutory right under the Representation of the People Act. In Kuldip Nayar (2006) and Jyoti Basu (1982), it said voting and contesting are statutory rights. Notice that the freedom to express one's vote, such as the NOTA option, is protected under Article 19(1)(a) (PUCL, 2013).
(d) has support in Kuldip Nayar (2006), where the Court called these rights statutory. UPSC's answer rests on Article 326.
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Answer as per the official UPSC answer key.
Four tests—Physics, Chemistry, Mathematics and Biology are to be conducted on four consecutive days, not necessarily in the same order. The Physics test is held before the test which is conducted after Biology. Chemistry is conducted exactly after two tests are held. Which is the last test held?
Answer (c) & explanation
Mathematics is the last test (c). Step 1: "Chemistry is conducted exactly after two tests" means Chemistry is on day 3. Step 2: "Physics is held before the test which is conducted after Biology." So Biology is followed by some test, and Physics comes before that test. The only way to fit this with Chemistry on day 3 is Physics on day 1 and Biology on day 2. Then Chemistry, on day 3, follows Biology, and Physics is before it. Step 3: so Mathematics is on day 4. Options (a) Physics, (b) Biology and (d) Chemistry hold days 1, 2 and 3.
Tip: fix the item with an exact position first, then fit the rest around it.
Answer as per the official UPSC answer key.
Read the passage
An innovative India will be inclusive as well as technologically advanced, improving the lives of all Indians. Innovation and R&D can mitigate increases in social inequality and relieve the pressures created by rapid urbanization. The growing divergence in productivity between agriculture and knowledge-intensive manufacturing and services threatens to increase income inequality. By encouraging India’s R&D labs and universities to focus on the needs of poor people and by improving the ability of informal firms to absorb knowledge, an innovation and research agenda can counter this effect. Inclusive innovation can lower the costs of goods and services and create income-earning opportunities for the poor people.
Which among the following is the most logical and rational assumption that can be made from the above passage?
Answer (c) & explanation
The assumption is that inclusive innovation and R&D can help create a fairer society (c). Step 1: the passage says innovation "can mitigate increases in social inequality" and create income for the poor. So it can help build an egalitarian society. That is option (c). Step 2: option (a) says innovation is the only way to reduce rural-urban migration, and option (d) says urbanisation happens only with rapid growth. Both use "only". Step 3: option (b) widens India's case to every rapidly growing country, which the passage does not do.
Tip: "inclusive innovation" means low-cost ideas that reach the poor, like cheap medical devices. Reject options with "only" and "every" unless the passage says so.
Answer as per the official UPSC answer key.
(Same information as the question above.)
In how many different ways can a train travel from F to A without passing through any station more than once?
Answer (d) & explanation
There are 4 ways from F to A (d). Step 1: from F, the only way out is the two-way passage to D. B to F is one-way into F. Step 2: from D, a train can go to E or to H. Step 3: list the routes without repeating stations: F–D–E–A, F–D–E–C–A, F–D–E–G–C–A and F–D–H–G–C–A. That is 4 routes. Options (a), (b) and (c) undercount.
Tip: in route counting, branch at each station and follow every path to the end. Strike out paths that repeat a station or go the wrong way on a one-way passage. A neat tree diagram stops you missing any route.
Answer as per the official UPSC answer key.
With reference to river Teesta, consider the following statements :
- 1. The source of river Teesta is the same as that of Brahmaputra but it flows through Sikkim.
- 2. River Rangeet originates in Sikkim and it is a tributary of river Teesta.
- 3. River Teesta flows into Bay of Bengal on the border of India and Bangladesh.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Only statement 2 is correct (b). Statement 1 is wrong because the Teesta rises from glaciers and lakes in north Sikkim, such as Tso Lhamo/Cholamu and the Zemu glacier near Kangchenjunga. The Brahmaputra starts at the Chemayungdung glacier near Mansarovar in Tibet. Statement 2 is right because the Rangeet rises in west Sikkim and joins the Teesta near the Sikkim–West Bengal border. Statement 3 is wrong because the Teesta flows into the Brahmaputra (Jamuna) inside Bangladesh, not straight into the Bay of Bengal.
The Teesta water-sharing deal with Bangladesh is still unsigned because of West Bengal's objections. Notice the related events: the South Lhonak GLOF in October 2023 destroyed the Chungthang dam, and China has offered to fund Teesta projects in Bangladesh.
Answer as per the official UPSC answer key.
Which of the following statements best describes the term 'Scheme for Sustainable Structuring of Stressed Assets (S4A)', recently seen in the news ?
Answer (b) & explanation
S4A was an RBI scheme for reworking big companies' stressed loans (b). The Scheme for Sustainable Structuring of Stressed Assets, launched in June 2016, let banks split a large stressed loan of over ₹500 crore into two parts. The sustainable part was what the company's cash flows could repay. The unsustainable part was turned into equity or similar instruments. It was not about ecological costs (a) or disinvestment (c). It was not part of the IBC (d); it was one of several restructuring schemes before the IBC.
The RBI scrapped all such schemes, including CDR and SDR, in February 2018. Notice how stressed loans are handled now: the IBC, the RBI's June 2019 framework, and the NARCL "bad bank" (2021).
"Sustainable" makes option (a) look ecological. The words "Stressed Assets" point to bank loans.
Answer as per the official UPSC answer key.
Which of the following is geographically closest to Great Nicobar ?
Answer (a) & explanation
Sumatra is closest to Great Nicobar (a). Indira Point, the southern tip of Great Nicobar and India's southernmost point, is only about 150 km from the northern tip of Sumatra (Aceh), across the Great Channel. Borneo (b) and Java (c) are much farther east and south. Sri Lanka (d) is over 1,300 km away. Indira Point is also very close to the Malacca Strait, one of the world's busiest shipping lanes.
That nearness is why the Great Nicobar project, costing about ₹72,000 crore, plans an international transshipment port at Galathea Bay, an airport and a township. Notice the opposing concerns: forest loss, harm to leatherback turtles and corals, and the rights of the Shompen, a particularly vulnerable tribe.
Answer as per the official UPSC answer key.
Read the passage
A successful democracy depends upon widespread interest and participation in politics, in which voting is an essential part. To deliberately refrain from taking such an interest, and from voting, is a kind of implied anarchy; it is to refuse one’s political responsibility while enjoying the benefits of a free political society.
This passage relates to
Answer (a) & explanation
The passage is about the duty to vote (a). Step 1: it says not voting is "to refuse one's political responsibility". Responsibility means duty. So the passage stresses voting as a duty. That is option (a). Step 2: options (b) right to vote, (c) freedom to vote and (d) right to take part in politics all talk of rights or freedoms. Step 3: these options miss the passage's stress on obligation. A right can be used or left; a duty should be done.
Tip: in India voting is a legal right, not a legal duty. But passages often argue it is a moral duty. Read the tone words, like "responsibility", to decide.
Answer as per the official UPSC answer key.
A bag contains 20 balls. 8 balls are green, 7 are white and 5 are red. What is the minimum number of balls that must be picked up from the bag blindfolded (without replacing any of it) to be assured of picking at least one ball of each colour?
Answer (b) & explanation
You must pick 16 balls (b). Step 1: think of the worst case: the balls come out in the most unlucky order. Step 2: the unluckiest order gives all the balls of the two largest colours first: all 8 green and all 7 white. That is 15 balls with no red yet. Step 3: the 16th ball must be red, since only red balls are left. So 16 balls guarantee at least one of each colour. Option (a), 17, is more than needed. Option (c), 13, and option (d), 11, could still miss a colour.
Tip: for "to be sure" questions, assume the worst luck. Take all of the biggest groups first, then add one more ball.
Answer as per the official UPSC answer key.
Which of the following gives ‘Global Gender Gap Index’ ranking to the countries of the world ?
Answer (a) & explanation
The World Economic Forum ranks countries on the gender gap (a). Its Global Gender Gap Report, published every year since 2006, scores countries on four areas: economic participation and opportunity, educational attainment, health and survival, and political empowerment. Iceland has topped it for over a decade, and India usually ranks in the bottom third, at 131st in 2025. The UN Human Rights Council (b), UN Women (c) and the WHO (d) do not publish this index.
The UNDP publishes the separate Gender Inequality Index and the Gender Development Index in its Human Development Report. Notice the WEF's other reports to keep apart: the Global Risks Report, the Energy Transition Index and, until 2019, the Global Competitiveness Report.
Answer as per the official UPSC answer key.
Democracy's superior virtue lies in the fact that it calls into activity
Answer (a) & explanation
Democracy calls on the intelligence and character of ordinary people (a). Democracy rests on the belief that ordinary citizens can judge public questions and take part in their own government. By asking them to vote, debate and hold power to account, it develops their intelligence and character. This was J. S. Mill's main defence of representative government. Strengthening executive leadership (b), relying on one dynamic leader (c), or relying on a band of party workers (d) all describe forms of rule by the few.
Notice how the Constitution builds this trust: universal adult franchise from 1950, with no literacy or property test, at a time when most Indians could not read. Ambedkar warned that political democracy must grow into social democracy.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. In the election for Lok Sabha or State Assembly, the winning candidate must get at least 50 percent of the votes polled, to be declared elected.
- 2. According to the provisions laid down in the Constitution of India, in Lok Sabha, the Speaker's post goes to the majority party and the Deputy Speaker's to the Opposition.
Which of the statements given above is/are correct?
Answer (d) & explanation
Neither statement is correct (d). Statement 1 is wrong because India uses the first-past-the-post system for Lok Sabha and Assembly elections. The candidate with the most votes wins, even with far less than 50% when many candidates split the vote. Statement 2 is wrong because the Constitution only says the House shall choose a Speaker and a Deputy Speaker from among its members (Article 93; Article 178 for States). Giving the Deputy Speaker's post to the opposition is only a convention, and it has often been ignored. The 17th Lok Sabha (2019–24) had no Deputy Speaker at all.
Notice where India uses proportional representation instead: the Rajya Sabha, the President's election, and the Vice-President's election, all through a single transferable vote.
Answer as per the official UPSC answer key.
Read the passage
During the summer in the Arctic Ocean, sea ice has been melting earlier and faster, and the winter freeze has been coming later. In the last three decades, the extent of summer ice has declined by about 30 per cent. The lengthening period of summer melt threatens to undermine the whole Arctic food web, atop which stand polar bears.
Which among the following is the most crucial message conveyed by the above passage?
Answer (d) & explanation
The crucial message is that climate change threatens the survival of polar bears (d). Step 1: the passage says the longer melt season "threatens to undermine the whole Arctic food web, atop which stand polar bears". So the bears' survival is at risk. Step 2: option (a) says Arctic summer is getting shorter. The passage says it is getting longer. Step 3: option (c) reverses cause and effect: the food web supports the bears, not the other way round. Option (b), moving bears to the South Pole, is never suggested.
Tip: watch for options that flip a fact (longer to shorter) or reverse a cause. These small changes are common traps.
Answer as per the official UPSC answer key.
There are thirteen 2-digit consecutive odd numbers. If 39 is the mean of the first five such numbers, then what is the mean of all the thirteen numbers?
Answer (a) & explanation
The mean of all thirteen numbers is 47 (a). Step 1: for evenly spaced numbers, the mean equals the middle term. The first five have mean 39, so 39 is their middle (3rd) number. The five are 35, 37, 39, 41 and 43. Step 2: the thirteen numbers start at 35 and go up by 2: 35, 37, … up to 59. Step 3: their middle term is the 7th one: 35 + 6 × 2 = 47. So the mean is 47. Options (b) 49 and (c) 51 are too high. Option (d), 45, is too low.
Tip: in any evenly spaced list, mean = middle term = (first + last) ÷ 2. Here (35 + 59) ÷ 2 = 47, which checks out.
Answer as per the official UPSC answer key.
Read the passage
Really I think that the poorest he that is in England has a life to live, as the greatest he, and therefore truly, I think it is clear that every man that is to live under a government ought first by his own consent to put himself under the government, and I do think that the poorest man in England is not at all bound in a strict sense to that government that he has not had a voice to put himself under.
The above statement argues for
Answer (b) & explanation
The statement argues for rule by the consent of the governed (b). Step 1: it says every man should live under a government only "by his own consent". That is government by consent. Option (b) states it. Step 2: the statement mentions "the poorest man" to show that even he has equal standing. It does not ask for rule of the poor (c). Step 3: options (a) equal wealth and (d) taking property from the rich are about money, which the statement does not discuss.
Tip: this idea comes from the Putney Debates in 17th-century England. "Consent of the governed" is the base of modern democracy, where people elect their rulers.
Answer as per the official UPSC answer key.
With reference to the 'Prohibition of Benami Property Transactions Act, 1988 (PBPT Act)', consider the following statements :
- 1. A property transaction is not treated as a benami transaction if the owner of the property is not aware of the transaction.
- 2. Properties held benami are liable for confiscation by the Government.
- 3. The Act provides for three authorities for investigations but does not provide for any appellate mechanism.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Only statement 2 is correct (b). The 2016 amendment to the Benami Act made benami property liable to confiscation by the government (2), along with jail of up to seven years and fines. Statement 1 is wrong because a transaction where the owner denies knowing about it, or which is held in a fictitious name, is specifically counted as benami. Statement 3 is wrong because the Act sets up four authorities: the Initiating Officer, Approving Authority, Administrator and Adjudicating Authority. It also provides an Appellate Tribunal, with further appeal to the High Court.
In Ganpati Dealcom (2022), the Supreme Court said the 2016 changes cannot apply to past transactions and struck down the 1988 penalty clause. Notice the link with India's fight against black money, alongside demonetisation and the Black Money Act, 2015.
Answer as per the official UPSC answer key.
Mediterranean Sea is a border of which of the following countries ?
- 1. Jordan
- 2. Iraq
- 3. Lebanon
- 4. Syria
Select the correct answer using the code given below :
Answer (c) & explanation
Only Lebanon and Syria border the Mediterranean (c). Lebanon (3) has a coastline with Beirut, Tyre and Sidon, and Syria (4) has its coast at Latakia and Tartus. Jordan (1) is almost landlocked, reaching the sea only at Aqaba on the Gulf of Aqaba (Red Sea). Iraq (2) reaches the sea only at the head of the Persian Gulf, near Basra and Umm Qasr. So any option with 1 or 2 is wrong.
Other countries on the eastern Mediterranean are Israel, Turkey, Egypt and the Gaza Strip. Notice the map points that matter today: Haifa port (Adani-run, part of IMEC), Russia's naval base at Tartus, and the Suez Canal linking the Mediterranean to the Red Sea.
Jordan sits right next to the Levant coast, but its only sea access is Aqaba on the Red Sea.
Answer as per the official UPSC answer key.
What is the purpose of ‘evolved Laser Interferometer Space Antenna (eLISA)’ project ?
Answer (b) & explanation
eLISA is meant to detect gravitational waves (b). The evolved Laser Interferometer Space Antenna, now just LISA, is a European Space Agency mission, with NASA as a partner, planned for launch in the mid-2030s. It will use three spacecraft about 2.5 million km apart, linked by lasers, to pick up low-frequency gravitational waves from merging supermassive black holes. Ground-based LIGO, which first detected gravitational waves in 2015 (Nobel 2017), cannot sense these. Neutrinos (a) are studied by detectors like IceCube and the proposed INO. Missile defence (c) and solar flares (d) are unrelated.
Gravitational waves were predicted by Einstein in 1916. Notice LIGO-India at Hingoli, Maharashtra, approved in 2023, which will join the global detector network.
Answer as per the official UPSC answer key.
The sum of income of A and B is more than that of C and D taken together. The sum of income of A and C is the same as that of B and D taken together. Moreover, A earns half as much as the sum of the income of B and D. Whose income is the highest?
Answer (b) & explanation
B has the highest income (b). Step 1: A earns half of B + D, so B + D = 2A. Also A + C = B + D, so A + C = 2A, which gives C = A. Step 2: A + B > C + D. Since C = A, this becomes B > D. Step 3: B + D = 2A and B > D, so B is above A and D is below A. So B > A = C > D, and B is highest. Option (a) A and option (c) C are equal and in the middle. Option (d) D is the lowest.
Tip: turn each sentence into an equation and substitute step by step. Finding that two people earn the same simplifies everything else.
Answer as per the official UPSC answer key.
Read the passage
Climate change is likely to expose a large number of people to increasing environmental risks forcing them to migrate. The international community is yet to recognize this new category of migrants. There is no consensus on the definition and status of climate refugees owing to the distinct meaning the term refugees carry under international laws. There are still gaps in understanding how climate change will work as the root cause of migration. Even if there is recognition of climate refugees, who is going to provide protection? More emphasis has been given to international migration due to climate change. But there is a need to recognize the migration of such people within the countries also so that their problems can be addressed properly.
Which of the following is the most rational inference from the above passage?
Answer (d) & explanation
The rational inference is that the link between climate change and migration is not yet properly understood (d). Step 1: the passage says: "there are still gaps in understanding how climate change will work as the root cause of migration". That is option (d). Step 2: option (c) calls climate change the most important reason for future migration. The passage never ranks it. Step 3: option (a), that the world cannot cope with climate refugees, is not stated. Option (b), stopping climate change, is a call to action the passage does not make.
Tip: when a passage admits "gaps in understanding", the safe inference is that the issue is uncertain. Options that claim certainty, like "most important", go too far.
Answer as per the official UPSC answer key.