OPSC ASO 2015 Question Paper with Answers

Question 1

Who is the Director General of WTO ?

1. (a) Roberto Azevedo
2. (b) Gabriel Duque
3. (c) Harald Neple
4. (d) Stephen Karau

Answer: (A) Roberto Azevedo

• (A) ✓ Brazil's Roberto Azevêdo became the sixth WTO Director-General on 1 September 2013, so he held the post when this paper was set.
• (B), (C), (D) ✗ Gabriel Duque (Colombia), Harald Neple (Norway) and Stephen Karau (Kenya) were ambassadors to the WTO. In late 2015 the three were named facilitators to help draft the declaration for the Nairobi Ministerial Conference. None of them headed the WTO.

The trap: all four names appeared in WTO news in 2015. Only one was the Director-General, the chief executive who heads the Secretariat in Geneva.

> Changed since: Azevêdo stepped down a year early, on 31 August 2020. Ngozi Okonjo-Iweala of Nigeria took over on 1 March 2021, the first woman and the first African in the post. Her second term began on 1 September 2025.

Question 2

Who was the first Odia to sail overseas ?

1. (a) Sarangadhar Das
2. (b) Gopabandhu Das
3. (c) Madhusudan Das
4. (d) Biswanath Das

Answer: (C) Madhusudan Das

• (C) ✓ Madhusudan Das (1848–1934), "Utkal Gourav", sailed to England in 1897 to put Odisha's case before the British government, and went again about ten years later. Odisha's own records call him the first Odia to go abroad.
• (A) ✗ Sarangadhar Das went abroad to study, in Japan and then the USA, only in the 1900s.
• (B) ✗ Gopabandhu Das, "Utkalmani", is known for the Satyabadi school and the newspaper Samaja, not for a voyage overseas.
• (D) ✗ Biswanath Das became the first Premier of Orissa province in 1937.

The trap: all four are famous Odia leaders named Das. Link "first" with the oldest of them: Madhusudan Das was also the first Odia graduate.

Question 3

Who is the President of South Africa ?

1. (a) Jacob Zuma
2. (b) Hailemariam Dessaleng
3. (c) Navtej Sarna
4. (d) None of the above

Answer: (A) Jacob Zuma

• (A) ✓ Jacob Zuma was President of South Africa from May 2009 to February 2018, so he was in office when this paper was set.
• (B) ✗ Hailemariam Desalegn (the paper spells it "Dessaleng") was Prime Minister of Ethiopia, not South Africa.
• (C) ✗ Navtej Sarna is an Indian diplomat and author.
• (D) ✗ With (A) correct, "None of the above" fails.

The trap: OPSC mixed in another African leader and an Indian name. Ask which country each person belongs to and only one fits.

> Changed since: Zuma resigned on 14 February 2018. Cyril Ramaphosa has been President since 15 February 2018, and Parliament re-elected him after the 2019 and 2024 general elections.

Question 4

Who is the author of the book, ‘Dreaming Big : A Journey to Connect India’ ?

1. (a) Chetan Bhagat
2. (b) Sashi Tharoor
3. (c) Sam Pitroda
4. (d) Meghnad Shah

Answer: (C) Sam Pitroda

• (C) ✓ Telecom pioneer Sam Pitroda published his memoir Dreaming Big: My Journey to Connect India with Penguin in 2015, written with David Chanoff.
• The paper prints the subtitle as "A Journey"; the book says "My Journey". The slip does not change the answer.
• (A) ✗ Chetan Bhagat writes novels such as Five Point Someone.
• (B) ✗ Shashi Tharoor (printed "Sashi") wrote The Great Indian Novel and other books, not this memoir.
• (D) ✗ "Meghnad Shah" is a made-up mix of Meghnad Saha, the scientist, and Meghnad Desai, the economist.

The trap: without the clue, a famous author like Tharoor feels safe. "Connect India" points to the man behind the yellow STD/PCO booths that put phones in every town in the 1980s.

Question 5

Who is Kaushik Basu ?

1. (a) Film Director
2. (b) Finance Minister of West Bengal
3. (c) The World Bank Chief Economist
4. (d) None of the above

Answer: (C) The World Bank Chief Economist

• (C) ✓ Kaushik Basu was Chief Economist and Senior Vice-President of the World Bank from 2012 to 2016.
• Before that he was Chief Economic Adviser to the Government of India (2009–2012).
• (A) ✗ He is an economist, not a film director.
• (B) ✗ West Bengal's Finance Minister then was Amit Mitra.
• (D) ✗ Option (C) fits, so "None of the above" fails.

The trap: a Bengali name pulls students towards (B). Remember Basu's two big posts: economic adviser in Delhi, then chief economist in Washington.

> Changed since: Basu left the World Bank in 2016 and went back to teaching at Cornell University. The World Bank's Chief Economist since 1 September 2022 is Indermit Gill.

Question 6

Who is the first Woman President of Nepal ?

1. (a) Onsari Gharti
2. (b) Bidhya Devi Bhandari
3. (c) Ram Kumari Jhakri
4. (d) Hisila Yami

Answer: (B) Bidhya Devi Bhandari

• (B) ✓ Nepal's Parliament elected Bidhya Devi Bhandari on 28 October 2015, making her the country's first woman President. She was re-elected in 2018 and served till March 2023.
• (A) ✗ Onsari Gharti Magar became Nepal's first woman Speaker in the same month, October 2015.
• (C), (D) ✗ Ram Kumari Jhakri and Hisila Yami are Nepali women politicians; neither became President.
• Bhandari took office under Nepal's new Constitution of 2015, which made the country a federal democratic republic. She followed Ram Baran Yadav, the first President.

The trap: two firsts for women came weeks apart. Fix which office each woman held: Speaker (Gharti) or President (Bhandari).

Question 7

National Institution for Transforming India Aayog was formed on :

1. (a) 26th January, 2015
2. (b) 30th January, 2015
3. (c) 1st April, 2015
4. (d) 1st January, 2015

Answer: (D) 1st January, 2015

• (D) ✓ A Union Cabinet resolution dated 1 January 2015 created NITI Aayog. It replaced the Planning Commission, which had worked since 15 March 1950.
• (A) ✗ 26 January is Republic Day; no NITI link.
• (B) ✗ 30 January is Martyrs' Day, Gandhi's death anniversary.
• (C) ✗ 1 April starts the financial year. It tempts because planning follows budget years, but NITI came three months earlier.
• Its first Governing Council meeting, with the Chief Ministers, was on 8 February 2015.

The trap: NITI Aayog has no founding Act, so there is no Parliament date to recall. The date to learn is New Year's Day 2015.

Question 1

Direction (Q. Nos. 1 & 2) : Choose a correct sequence of ascending order of magnitude.

2¹², 3⁸, 4⁷, 10³ :

1. (a) 2¹², 3⁸, 10³, 4⁷
2. (b) 10³, 2¹², 4⁷, 3⁸
3. (c) 10³, 2¹², 3⁸, 4⁷
4. (d) 10³, 4⁷, 2¹², 3⁸

Answer: (C) 10³, 2¹², 3⁸, 4⁷

Work out each value:

• 10³ = 1000
• 2¹² = 2¹⁰ × 4 = 1024 × 4 = 4096
• 3⁸ = (3⁴)² = 81 × 81 = 6561
• 4⁷ = 2¹⁴ = 4096 × 4 = 16384

Ascending: 1000 < 4096 < 6561 < 16384.

• (A) ✗ puts 1000 third, though it is the smallest.
• (B) ✗ puts 4⁷ before 3⁸; 16384 is more than twice 6561.
• (D) ✗ puts 4⁷ second; it is the largest.

Fastest: 4⁷ = 2¹⁴ is 4 times 2¹², so it goes last. 3⁸ = 6561 falls between 4096 and 16384, and 10³ is clearly first.

The trap: judging by the exponent alone. 2¹² has the biggest power but not the biggest value; the base matters just as much.

Question 2

Direction (Q. Nos. 1 & 2) : Choose a correct sequence of ascending order of magnitude.

Trillion, Million, Billion, Thousand :

1. (a) Trillion, Thousand, Billion, Million
2. (b) Trillion, Million, Billion, Thousand
3. (c) Thousand, Billion, Million, Trillion
4. (d) Thousand, Million, Billion, Trillion

Answer: (D) Thousand, Million, Billion, Trillion

In the international system each name is 1000 times the one before it:

• (A) ✗ starts with Trillion, the largest.
• (B) ✗ repeats the question's own order, which runs largest first.
• (C) ✗ puts Billion before Million, though a billion is a thousand millions.

The trap: reading the direction as descending order. "Ascending order of magnitude" means smallest to largest, and the question lists the words in a jumbled order on purpose.

Question 3

Direction (Q. Nos. 3 & 4) : In each of the following number series, a wrong number is given. Find out the wrong number.

2, 6, 12, 18, 30, 42 :

1. (a) 6
2. (b) 12
3. (c) 18
4. (d) 30

Answer: (C) 18

Each term is n × (n + 1):

• 1 × 2 = 2, 2 × 3 = 6, 3 × 4 = 12
• 4 × 5 = 20, but the paper shows 18
• 5 × 6 = 30, 6 × 7 = 42

The gaps confirm it. With 20 in place they are 4, 6, 8, 10, 12, rising by 2 each time. With 18 they are 4, 6, 6, 12, 12: no pattern.

• (A) 6, (B) 12, (D) 30 ✗ all fit n × (n + 1). Change any one of them and 18 still breaks the series.

The trap: 6, 12, 18 look like the 6 times table, which makes 30 or 42 look out of place. But that idea fails at the first term, 2, and would need more than one term changed. Only one term may be wrong.

Question 4

Direction (Q. Nos. 3 & 4) : In each of the following number series, a wrong number is given. Find out the wrong number.

2, 3, 5, 7, 9, 11, 13, 17, 19 :

1. (a) 2
2. (b) 9
3. (c) 11
4. (d) 19

Answer: (B) 9

The series is the list of prime numbers in order: numbers with exactly two factors, 1 and themselves.

• 2, 3, 5, 7, 11, 13, 17, 19 are all prime.
• 9 = 3 × 3 has a third factor, 3, so it is not prime.
• Remove 9 and the list is exactly the first eight primes, with none missing.

• (A) 2 ✗ is prime, the only even prime.
• (C) 11, (D) 19 ✗ are prime.

The trap: 2 is the only even number in the list, so it looks like the odd one out. But the rule here is primality, not odd and even: 2 is prime and 9 is not.

Question 5

In the series :
861238742157862171413286
how many pairs of successive numbers have a difference of 2 each ?

1. (a) 3
2. (b) 4
3. (c) 5
4. (d) 6

Answer: (D) 6

The string has 24 digits, so 23 neighbouring pairs. Those that differ by 2:

Every other pair differs by 1, 3, 4, 5 or 6. Total = 6.

• (B) 4 ✗ counts only the falling pairs (8 6, 4 2, 8 6, 8 6).
• (A) 3, (C) 5 ✗ miss pairs; the last 8 6 is the easiest one to drop.

The trap: "a difference of 2" works both ways. 5 7 and 1 3 rise by 2 and still count.

Question 6

Lata ranked eighth from the top and thirty ninth from the bottom in a class. How many students are there in a class ?

1. (a) 45
2. (b) 46
3. (c) 47
4. (d) 48

Answer: (B) 46

• Eighth from the top: 7 students are above Lata.
• Thirty-ninth from the bottom: 38 students are below her.
• Total = 7 + 1 + 38 = 46.

Formula: total = rank from top + rank from bottom − 1 = 8 + 39 − 1 = 46.

Check: rank from bottom = 46 − 8 + 1 = 39 ✓.

• (C) 47 ✗ adds 8 + 39 and counts Lata twice.
• (D) 48 ✗ adds 1 instead of subtracting it.
• (A) 45 ✗ subtracts 2 and leaves Lata out.

The trap: 8 + 39 = 47 is the number that jumps out, and it is offered as (C). Both ranks already include Lata, so she must be taken away once.

Question 1

The decimal expansion of 23/(2³ · 5²) will terminate after :

1. (a) One-decimal place
2. (b) Two-decimal place
3. (c) Three-decimal place
4. (d) Four-decimal place

Answer: (C) Three-decimal place

• Denominator: 2³ · 5² = 8 × 25 = 200.
• Make a power of 10: multiply the top and the bottom by one more 5: (23 × 5)/(2³ × 5³) = 115/1000 = 0.115.
• Rule: if the denominator (in lowest terms) is 2ⁿ 5^m, the decimal stops after the larger of n and m places. Here the larger power is 3.
• (A), (B) ✗ stop too early: 0.115 needs three digits after the point.
• (D) ✗ four places would need 2⁴ or 5⁴ in the denominator.

The trap: taking the smaller power (2, option B) or adding the powers (3 + 2 = 5). The larger power decides, because you only top up the smaller one to match it.

Fastest: max(3, 2) = 3 places.

Question 2

3 + 2√5 is :

1. (a) An irrational number
2. (b) A rational number
3. (c) Neither rational nor irrational number
4. (d) Whole number

Answer: (A) An irrational number

• Start with √5: 5 is not a perfect square, so √5 is irrational.
• Proof by contradiction: suppose 3 + 2√5 = r, a rational number. Then √5 = (r - 3)/2, which would be rational. That is false, so 3 + 2√5 is irrational.
• (B) ✗ fails by the same contradiction.
• (C) ✗ every real number is either rational or irrational; there is no third kind.
• (D) ✗ 3 + 2√5 ≈ 3 + 4.47 = 7.47, not a whole number.

The trap: thinking the rational 3 somehow "cancels" the surd. Rational + (non-zero rational × irrational) is always irrational.

Question 3

For a and b being co-prime, then a² and b² are :

1. (a) May or may not be co-prime
2. (b) Never co-prime
3. (c) Always co-prime
4. (d) None of the above

Answer: (C) Always co-prime

• Co-prime means HCF = 1: no prime factor in common.
• Squaring keeps the primes: if a = 2² × 3, then a² = 2⁴ × 3². The same primes appear, only with higher powers.
• So if a and b share no prime, a² and b² share none either, and the HCF stays 1.
• Example: 8 and 15 are co-prime; 64 and 225 are also co-prime.
• (A) ✗ there is no case where a common factor appears.
• (B) ✗ 2 and 3 give 4 and 9, which are co-prime.
• (D) ✗ not needed, since (C) is true.

The trap: "may or may not" sounds safe. A property that follows from prime factorisation holds always, so there is nothing to hedge.

Question 4

The least number that is divisible by all the numbers from 1 to 10 (both inclusive) is :

1. (a) 10
2. (b) 252
3. (c) 504
4. (d) 2520

Answer: (D) 2520

• "Least number divisible by all" = the LCM of 1, 2, …, 10.
• Highest prime powers up to 10: 2³ = 8, 3² = 9, 5 and 7.
• Multiply: 8 × 9 × 5 × 7 = 72 × 35 = 2520.
• Check: 2520 ÷ 8 = 315, ÷ 9 = 280, ÷ 7 = 360, ÷ 10 = 252, all whole.
• (A) 10 ✗ fails 3, 4, 6, 7, 8 and 9.
• (B) 252 ✗ = 2² × 3² × 7: no 5, and only 2².
• (C) 504 ✗ = 2³ × 3² × 7: has 8, 9 and 7 but no 5.

The trap: multiplying 1 × 2 × … × 10 (3628800), or forgetting that 8 needs three 2s and 9 needs two 3s.

Fastest: the answer must end in 0 to be divisible by 10. Only 10 and 2520 do, and 10 fails 3.

Question 5

In Euclid’s Division Lemma, a = bq + r, 0 ≤ r < b, the numbers ‘a’ and ‘r’ are the :

1. (a) Divisor and Dividend
2. (b) Dividend and Remainder
3. (c) Quotient and Divisor
4. (d) Remainder and Quotient

Answer: (B) Dividend and Remainder

• Lemma: for positive integers a and b there are unique integers q and r with a = bq + r and 0 ≤ r < b.
• Read it as division: dividend = divisor × quotient + remainder.
• Example: 17 = 5 × 3 + 2: a = 17 is the dividend, b = 5 the divisor, q = 3 the quotient and r = 2 the remainder.
• (A) ✗ calls a the divisor: that is b.
• (C) ✗ describes q and b, not a and r.
• (D) ✗ r is the remainder, but the quotient is q.

The trap: mixing up q and b, which sit side by side in bq. Keep the plain sentence in mind: dividend = divisor × quotient + remainder, with the remainder smaller than the divisor.

Question 6

If ‘a’ and ‘b’ be two odd prime numbers, then (a² - b²) is :

1. (a) An even prime
2. (b) An odd prime
3. (c) Prime
4. (d) Composite

Answer: (D) Composite

• Parity: odd² is odd, and odd − odd = even.
• Factorise: a² - b² = (a - b)(a + b). Both brackets are even, so the product is a multiple of 4 (in fact of 8).
• Example: a = 7, b = 3: 49 - 9 = 40; a = 5, b = 3: 25 - 9 = 16. Both composite.
• (A) ✗ the only even prime is 2, and a multiple of 4 cannot be 2.
• (B) ✗ the result is even, not odd.
• (C) ✗ an even number above 2 is never prime.

The trap: the wording. The question assumes two different primes with a > b. If a = b the value is 0, and if a < b it is negative; neither is called prime or composite. Read it the intended way and only (D) fits.

Question 1

The train from New Delhi is late by 2 hours. What question would you make in order to get this answer ?

1. (a) Is the train from New Delhi late ?
2. (b) How late is the train from New Delhi ?
3. (c) When will the train from New Delhi arrive ?
4. (d) Where will the late train arrive from ?

Answer: (B) How late is the train from New Delhi ?

• (B) ✓ The answer gives a measure of delay: late by 2 hours. The question word for a degree or an amount is how + adjective: how late, how long, how far.
• (A) ✗ A yes/no question is answered "Yes, it is." It would never draw out the 2 hours.
• (C) ✗ When asks for a point in time ("at 6 p.m."), not for the length of the delay.
• (D) ✗ Where ... from asks for a place. New Delhi is already known; it is not what the answer supplies.

The trap: (A) repeats almost every word of the answer, so it feels safe. A question must aim at the new information in the reply, and here that is the 2 hours.

Question 2

Sam hasn't won this election, ________ ?
(Fill in the blank choosing the correct words)

1. (a) has he
2. (b) hasn't he
3. (c) was he
4. (d) can he

Answer: (A) has he

• (A) ✓ A question tag copies the auxiliary of the statement and flips it. The statement uses hasn't (negative), so the tag is positive: "Sam hasn't won this election, has he?"
• (B) ✗ Hasn't he keeps the negative. A negative tag belongs after a positive statement: "Sam has won, hasn't he?"
• (C) ✗ Was he changes the auxiliary. The verb is present perfect (has won), so the tag must use has.
• (D) ✗ Can he brings in a modal the sentence never had.

The trap: students see hasn't and echo it. Use the rule of opposites: positive → negative tag, negative → positive tag, the same helping verb, and a pronoun for the subject (Sam → he).

Question 3

Choose the correct antonym of 'optimist' :

1. (a) Cynical
2. (b) Pessimist
3. (c) Realist
4. (d) Pragmatist

Answer: (B) Pessimist

• (B) ✓ An optimist expects things to turn out well; a pessimist expects them to turn out badly. Both are nouns for a person, so they make an exact pair.
• (A) ✗ Cynical is an adjective: distrustful of people's motives. It is negative in tone, but it is about distrust, not gloomy expectation, and it is the wrong part of speech.
• (C) ✗ A realist sits in the middle: neither hopeful nor gloomy, just facing the facts.
• (D) ✗ A pragmatist cares about what works in practice. That is a method, not an outlook.

The trap: (A) feels "negative", so it tempts. An antonym must be the opposite idea and the same part of speech: optimist (noun) ↔ pessimist (noun).

Question 4

Raju is quite smart and intelligent. His brother, however, is rather ________ and ________ .
(Fill in the blanks choosing the correct words)

1. (a) short, unintelligent
2. (b) unsmart, stupid
3. (c) slow and dull
4. (d) brisk and witty

Answer: (C) slow and dull

• (C) ✓ However sets up a contrast with "smart and intelligent". Here smart means quick-witted, so its opposite is slow; the opposite of intelligent is dull (slow to understand). "Rather slow and dull" is a natural, mild pairing.
• (B) ✗ Unsmart is not a standard word, so the pair does not read as good English, even though stupid fits the second blank.
• (A) ✗ Short describes height, not the mind. Only unintelligent contrasts.
• (D) ✗ Brisk and witty are compliments, so they contradict however.

The trap: students hunt for a word with un- in front, as in (A) and (B). Opposites are often separate words: smart ↔ slow, bright ↔ dull. Options (C) and (D) are printed as pairs joined by and; read them as blank one and blank two.

Question 5

Fill in the blank with the appropriate preposition :
The document has to be certified by an officer not ________ the rank of a Tehsildar.

1. (a) under
2. (b) above
3. (c) below
4. (d) over

Answer: (C) below

• (C) ✓ Not below the rank of a Tehsildar = a Tehsildar or any higher officer. It sets a minimum rank, which is what a certifying rule needs. It is the set phrase in Indian rules and forms.
• (A) ✗ Under can mean lower in rank, so it is the closest distractor. But for ranks and levels the fixed expression is below; "not under the rank of" is rare.
• (B) ✗ Not above sets a maximum: a Tehsildar or someone junior. That defeats the purpose of certification.
• (D) ✗ Over works like above here, and it is not used with rank in this phrase.

The trap: the word not flips the meaning, so read the phrase as "at least a Tehsildar". Below and above suit levels on a scale; under and over suit position and amounts.

Question 6

"Will you attend the meeting ?" he said. In reported speech this will be :

1. (a) He asked us whether we would attend the meeting.
2. (b) We asked us whether he would attend the meeting.
3. (c) He asked that if we will attend the meeting.
4. (d) We asked if he will attend the meeting.

Answer: (A) He asked us whether we would attend the meeting.

• (A) ✓ Three changes, all correct: said → asked (it is a question); a yes/no question is linked by whether/if; and will → would because the reporting verb is past. The direct speech names no listener, so (A) supplies us, and "you" becomes we.
• (B) ✗ We asked us is ungrammatical, and it turns the listener into the speaker.
• (C) ✗ That if joins two conjunctions: a reported question takes if/whether without that. Will is also left unshifted.
• (D) ✗ It makes we the speaker, and will is not backshifted.

The trap: (C) keeps "he asked" and "we", so it looks close. But that introduces reported statements; reported questions use if or whether.