Find out which of the following sets form co-prime numbers.
Show answer & explanation
Answer: (A) (12, 7)
Co-prime numbers have HCF 1. HCF(12, 7) = 1, while 21 and 42 share 21, 3 and 9 share 3, and 43 and 129 share 43 (129 = 3 × 43).
RRB NTPC CBT-II Official Paper (Held On: 18 Jan 2017 Shift 1) · 120 questions. Try each question, then open its answer.
Answer: (A) (12, 7)
Co-prime numbers have HCF 1. HCF(12, 7) = 1, while 21 and 42 share 21, 3 and 9 share 3, and 43 and 129 share 43 (129 = 3 × 43).
Answer: (A) 88 : 63
Take the salaries as 4x and 3x. After the raises: 4x × 1.10 = 4.4x and 3x × 1.05 = 3.15x. The ratio is 4.4 : 3.15 = 440 : 315 = 88 : 63.
Answer: (B) Indian National Congress
The Home Rule Leagues of Bal Gangadhar Tilak (1916) and Annie Besant (1916) worked within the national movement as auxiliary units of the Indian National Congress, demanding self-government.
Answer: (D) Wireless
Future payments are moving to wireless technology – mobile banking, UPI, NFC contactless cards and mobile wallets – so 'wireless' best completes the sentence.
Answer: (D) Purnima Devi Barman
Purnima Devi Barman, an Assamese wildlife biologist who leads community efforts ('Hargila Army') to save the Greater Adjutant stork, won the RBS Earth Heroes Award 2016.
Answer: (D) Atharvaved
The Atharvaveda contains charms and remedies for diseases and is regarded as the source of Ayurveda.
Answer: (D) SERCU
HORSE → SERHO takes letters 4, 5, 3, 1, 2 (S, E, R, H, O). Applying this to CURSE (C1 U2 R3 S4 E5) gives S, E, R, C, U = SERCU.
Answer: (B) 5/12
Together they do 1/15 + 1/20 = 4/60 + 3/60 = 7/60 of the work per day. In 5 days they finish 35/60 = 7/12, leaving 5/12 unfinished.
Answer: (B) Air Chief Marshal
An Admiral is the highest rank in the Navy; the matching top rank in the Indian Air Force is Air Chief Marshal.
Answer: (B) Both statements I and III are sufficient.
Statement I says today's index is below the lowest level of the last 3 years, and III gives that lowest level as 27,125. Together they show the index is below 27,125 – enough for an overall assessment. Statement II is not needed.
Answer: (C) 8,000
At the time of the exam Indian Railways had a little over 7,000 stations, so 'about 8,000' is the closest option.
Answer: (D) 2741845
From TEACHER = 8412745: T = 8, E = 4, A = 1, C = 2, H = 7, R = 5. So CHEATER = 2 7 4 1 8 4 5 = 2741845.
Answer: (D) 387
157, 571 and 599 are prime numbers. 387 = 3 × 3 × 43 is not prime, so it is the odd one.
Answer: (B) 2.5%
Each box cost 9600/8 = Rs 1200. Profit on 5 boxes = 5 × 120 = 600; loss on 3 boxes = 3 × 120 = 360. Net gain = 240, and 240/9600 × 100 = 2.5%.
Answer: (C) Astronomy
Hubble's Law (1929) states that galaxies recede at speeds proportional to their distance from us – evidence that the universe is expanding. It belongs to astronomy.
Answer: (D) Black-necked Cranes
In April 2016 the NGT suspended the clearance for the Nyamjang Chhu hydropower project in Tawang, Arunachal Pradesh, because the area is a wintering habitat of the vulnerable black-necked crane.
Answer: (C) communication
GSAT-18, launched on 6 October 2016 by Ariane 5 from French Guiana, is a communication satellite carrying 48 transponders.
Answer: (D) Assam
Majuli, a large river island in the Brahmaputra, was made a separate district of Assam in 2016 – India's first island district.
Answer: (B) Triple
In MS Word a double-click selects a word and a triple-click selects the whole paragraph.
Answer: (D) Juan Manuel Santos
Colombian President Juan Manuel Santos received the 2016 Nobel Peace Prize for his efforts to end the 50-year civil war with the FARC rebels.
Answer: (C) 44
The number must be divisible by LCM(6, 5, 4) = 60. The next multiple of 60 after 1456 is 1500 (60 × 25), so 1500 − 1456 = 44 must be added.
Answer: (A) Reptile
Snake, lizard and crocodile are all reptiles; 'reptile' is the class they belong to, so it is the odd one.
Answer: (C) 77.78%
Girls = 135/3 = 45 and boys = 90. Failed: 90/6 + 45/3 = 15 + 15 = 30, so 105 passed. 105/135 × 100 = 77.78%.
Answer: (B) 21
Let p = 4k and q = 3k. Their LCM is 12k = 36, so k = 3. Then p = 12, q = 9 and p + q = 21.
Answer: (D) ZDHLPT
Each letter of EIMQUY moves 2 places back to give CGKOSW. Moving each letter of BFJNRV 2 places back gives Z, D, H, L, P, T = ZDHLPT.
Answer: (B) Rs. 24,000
SP = 1.13 × CP, so CP = 27120/1.13 = Rs 24,000.
Answer: (A) Rs. 200
SI for 2 years at 10% is 4000, so P = 4000/(0.10 × 2) = Rs 20,000. CI = 20000 × (1.1² − 1) = 20000 × 0.21 = Rs 4,200, which is Rs 200 more.
Answer: (B) Rs. 9,500
The two selling prices differ by 9% − 7% = 2% of the cost price. 2% of CP = 190, so CP = Rs 9,500.
Answer: (D) Brother
The only son of the lady's grandfather is her father. The son of her father is her brother.
Answer: (A) Neymar
Neymar is Brazilian. Gabriel Batistuta, Marcos Rojo and Lionel Messi are Argentine footballers.
Answer: (A) ÷ and ×
Swapping ÷ and × gives 16 − 24 ÷ 2 × 10 + 104 = 16 − 120 + 104 = 0, which balances.
Answer: (D) Both statements I and II are sufficient.
From I and II: 3 shifts × 13 wards × 2 nurses = 78 nurses at minimum. Statement III is about the town, not the hospital, so I and II are sufficient.
Answer: (B) Protein
Rice is a major source of carbohydrate; sprouts (sprouted pulses and grams) are a rich source of protein.
Answer: (C) World Wildlife Fund
WWF was founded in 1961 as the World Wildlife Fund. Outside North America it is now called the World Wide Fund for Nature, keeping the initials WWF.
Answer: (B) investment
A Ponzi scheme is an investment fraud that pays earlier investors with money from new investors rather than real profits. It is named after Charles Ponzi.
Answer: (A) minus 273 °C
Absolute zero, 0 K, is the lowest possible temperature, about −273 °C (exactly −273.15 °C).
Answer: (C) Neil
Minicoy, Kavaratti and Amini are Lakshadweep islands. Neil Island (now Shaheed Dweep) is in the Andaman and Nicobar Islands.
Answer: (D) An apple is not as costly as a mango.
6 mangoes = 4 apples, so an apple costs 1.5 mangoes. 8 apples = 2 jackfruits, so a jackfruit costs 4 apples. Mango < apple < jackfruit, so 'an apple is not as costly as a mango' is NOT true.
Answer: (A) 25
1 man = 2 women, so 10 men + 5 women = 25 women, and the work = 25 × 60 = 1500 woman-days. 5 men + 20 women = 30 women, so half the work (750) takes 750/30 = 25 days.
Answer: (B) 11
In July 2016 Russian adventurer and priest Fedor Konyukhov flew solo round the world in a hot-air balloon in about 11 days, a world record.
Answer: (A) ODT
TIFF, PNG and PCX are bitmap (raster) image formats. ODT is the OpenDocument Text format used by word processors.
Answer: (B) Both I and II follow
All men are mechanics, so some mechanics are men (I follows). All mechanics are engineers, so some engineers are mechanics (II follows). Both follow.
Answer: (C) 15 days
The work = 15 × 60 = 900 person-days. With 20 persons it takes 900/20 = 45 days, i.e. 15 days earlier.
Answer: (B) LLHX
R→S (+1), M→L (−1), S→U (+2), K→I (−2). Applying the same steps to KMFZ: K→L, M→L, F→H, Z→X = LLHX.
Answer: (C) 1919
The Rowlatt Act was passed in March 1919, allowing detention without trial. Protest against it led to the Jallianwala Bagh massacre on 13 April 1919.
Answer: (A) 12,000
CI = P(1.2² − 1) = 0.44P = 5280, so P = Rs 12,000.
Answer: (D) Loss Rs. 100
2 pants + 4 shirts = 1 pant + 6 shirts, so 1 pant = 2 shirts. Then 8 shirts' worth = 5600, so a shirt costs Rs 700. Selling 10 shirts for 6000 means Rs 600 each – a loss of Rs 100 per shirt.
Answer: (A) 40 kmph
They meet 120 km from B, i.e. 360 − 120 = 240 km from A. Train P covers 240 km at 60 km/h in 4 hours, so they meet at 2 PM. Train Q, starting at 11 AM, covers 120 km in 3 hours, so its speed is 40 km/h.
Answer: (D) 35
Under Article 157, a person must be an Indian citizen who has completed 35 years of age to be appointed Governor.
Answer: (A) Harish
Combining the clues: Harish < Alpesh < Yogesh < Dharmesh < Ramesh < Suresh < Rajesh. Harish is the shortest.
Answer: (A) Dharmesh
The order of the seven by height is Harish, Alpesh, Yogesh, Dharmesh, Ramesh, Suresh, Rajesh. The 4th person, Dharmesh, is in the middle.
Answer: (C) HLTCO
The words are CLOVE, CHILLY, CLOTH and CUMIN. Clove, chilly and cumin are spices; CLOTH (HLTCO) is different.
Answer: (B) 2
Replacing the symbols: 9 × 3 + 22 − 52 + 85 ÷ 17 = 27 + 22 − 52 + 5 = 2.
Answer: (A) Khangchendzonga National Park, Sikkim
Khangchendzonga National Park in Sikkim was inscribed in July 2016 as India's first 'mixed' (natural and cultural) World Heritage Site.
Answer: (B) Either the Prime minister or a Minister who is nominated by the Prime Minister
The Leader of the House in Lok Sabha is the Prime Minister if he or she is a member of the House, or otherwise a minister nominated by the Prime Minister.
Answer: (A) Directional growth of a plant
Tropism is the directional growth of a plant part in response to a stimulus – towards light (phototropism), gravity (geotropism) or water (hydrotropism).
Answer: (A) 5√2, 4√3, 3√5, 2√11
As square roots: 2√11 = √44, 4√3 = √48, 3√5 = √45 and 5√2 = √50. Descending: √50, √48, √45, √44, i.e. 5√2, 4√3, 3√5, 2√11.
Answer: (A) Rs. 32,000
28% of the salary is Rs 8960, so the salary = 8960/0.28 = Rs 32,000.
Answer: (B) Father-in-law
Geni is the mother of Rita and Rosy, and Vaz is Rita's father, so Vaz is also Rosy's father. Sam is Rosy's husband, which makes Vaz his father-in-law.
Answer: (C) 13
Pranab Mukherjee was sworn in on 25 July 2012 as the 13th President of India, succeeding Pratibha Patil.
Answer: (D) Lending money
Payments banks may accept deposits (up to a limit), offer remittances and sell simple insurance and mutual funds, but they cannot lend money or issue credit cards.
Answer: (C) 6%
Interest = 5000 × 4 × r/100 + 4000 × 5 × r/100 = 200r + 200r = 400r. Setting 400r = 2400 gives r = 6%.
Answer: (B) Black Carbon
Scientists warned that the 2016 Uttarakhand forest fires released large amounts of black carbon (soot), which settles on Himalayan glaciers and speeds up their melting.
Answer: (C) Maharashtra
In August 2016 a British-era bunker with several rooms was discovered under the Raj Bhavan at Malabar Hill in Mumbai, Maharashtra.
Answer: (B) 11.2 km/sec
Escape velocity from Earth's surface, the minimum speed needed to escape its gravity, is about 11.2 km/s.
Answer: (B) PepsiCo
Indra Nooyi was Chairperson and CEO of PepsiCo from 2006 to 2018.
Answer: (B) Haryana
West Bengal borders Bangladesh, Nepal and Bhutan; Punjab borders Pakistan; Himachal Pradesh borders China (Tibet). Haryana has no international border.
Answer: (A) 24
The code is the sum of letter positions: EAR = 5 + 1 + 18 = 24 and EYE = 5 + 25 + 5 = 35. LEG = 12 + 5 + 7 = 24.
Answer: (D) Medium
Wavelength, amplitude and frequency are properties of a wave. The medium is what a mechanical wave travels through; it is not a characteristic of the wave, and light needs no medium at all.
Answer: (C) Fire
Birds fly in the sky, and in this code 'sky' is called 'fire'. So the answer is fire.
Answer: (A) 44 cm
Circumference = 2πr, so the increase = 2π × 7 = 2 × 22/7 × 7 = 44 cm.
Answer: (B) 6/7
3/5 = 0.6 and 7/8 = 0.875. 6/7 ≈ 0.857 lies between them; 8/9 ≈ 0.889 and 12/13 ≈ 0.923 are too large and 4/7 ≈ 0.571 is too small.
Answer: (D) Positrons
The antiparticle of the electron is the positron – same mass, but positive charge. It was predicted by Dirac and discovered by Anderson in 1932.
Answer: (C) 1/√3
sin 45° and cos 45° are equal (1/√2), so they cancel. The expression becomes sin 30°/cos 30° = tan 30° = (1/2)/(√3/2) = 1/√3.
Answer: (B) A real number need not necessarily be a point on the number line
Every real number corresponds to exactly one point on the number line and every point to one real number, so the statement that a real number need not be a point on the number line is NOT true.
Answer: (A) 2m, -2n
Let x = a/m and y = b/n. Then 2x + y = 2 and x − y = 4. Adding: 3x = 6, so x = 2 and y = −2. Hence a = 2m and b = −2n.
Answer: (D) 35
2/3 × 3/5 × N = 2N/5 = 42, so N = 105. One-third of 105 = 35.
Answer: (C) Inkjet printers
Gyroscopic sensors are used in smartphones (orientation), some air mice and in vehicles for stability control. An inkjet printer works without a gyroscope.
Answer: (B) 120
120 appears 4 times, more than any other value (100 appears 3 times), so the mode is 120.
Answer: (B) 15.56%
Discount = 90 − 76 = Rs 14. Discount % = 14/90 × 100 ≈ 15.56%.
| IT Company | No. of students hired | P (%) | Q (%) | R (%) | S (%) |
|---|---|---|---|---|---|
| I | 1800 | 24 | 32 | 28 | 16 |
| II | 2400 | 27 | 30 | 25 | 18 |
| III | 1500 | 32 | 20 | 25 | 23 |
What is the total number of students hired by Company II from Colleges P, R and S.
Answer: (D) 1680
Company II hired 2400; colleges P, R and S together account for 27 + 25 + 18 = 70%. 70% of 2400 = 1680.
| IT Company | No. of students hired | P (%) | Q (%) | R (%) | S (%) |
|---|---|---|---|---|---|
| I | 1800 | 24 | 32 | 28 | 16 |
| II | 2400 | 27 | 30 | 25 | 18 |
| III | 1500 | 32 | 20 | 25 | 23 |
Find the difference between the number of students hired by Companies II and III from College R.
Answer: (D) 225
From R: Company II = 25% of 2400 = 600, Company III = 25% of 1500 = 375. Difference = 225.
| IT Company | No. of students hired | P (%) | Q (%) | R (%) | S (%) |
|---|---|---|---|---|---|
| I | 1800 | 24 | 32 | 28 | 16 |
| II | 2400 | 27 | 30 | 25 | 18 |
| III | 1500 | 32 | 20 | 25 | 23 |
How many more students did all the three companies together hire from College P in comparison with College S?
Answer: (A) 495
From P: 24% of 1800 + 27% of 2400 + 32% of 1500 = 432 + 648 + 480 = 1560. From S: 288 + 432 + 345 = 1065. Difference = 495.
| IT Company | No. of students hired | P (%) | Q (%) | R (%) | S (%) |
|---|---|---|---|---|---|
| I | 1800 | 24 | 32 | 28 | 16 |
| II | 2400 | 27 | 30 | 25 | 18 |
| III | 1500 | 32 | 20 | 25 | 23 |
What is the difference between the number of students hired by Company III from College P and that hired by Company I from College Q?
Answer: (B) 96
Company III from P = 32% of 1500 = 480. Company I from Q = 32% of 1800 = 576. Difference = 96.
Answer: (B) Tamil Nadu
The Brihadeeswara Temple at Thanjavur, Tamil Nadu, was built by Chola king Rajaraja I in about 1010 CE and is a UNESCO World Heritage Site.
Answer: (D) Wular
Wular Lake in Jammu and Kashmir, fed by the Jhelum, is India's largest freshwater lake and one of the largest in Asia. Sambhar is salt and Chilika is brackish.
Answer: (A) Only conclusion II follows
If adversity is the best teacher, it gives opportunities to learn – II follows. Adversity is not the same as poverty, so I does not follow.
Answer: (A) 77
8 of the 85 read neither, so 85 − 8 = 77 read novels or poems (or both).
Answer: (D) 5
n(N ∩ P) = n(N) + n(P) − n(N ∪ P) = 45 + 37 − 77 = 5.
Answer: (B) 37
For identical batches of one nationality each with nobody left out, the batch size must divide 111, 407 and 259. HCF(111, 407, 259) = 37 (111 = 3 × 37, 407 = 11 × 37, 259 = 7 × 37), so each batch has 37 persons.
Answer: (D) Dr. Urjit R. Patel
Dr. Urjit R. Patel took charge as the 24th Governor of the RBI on 4 September 2016, succeeding Dr. Raghuram Rajan.
Answer: (A) 8%
Rate = SI × 100/(P × T) = 2040 × 100/(8500 × 3) = 8% per annum.
Answer: (D) CPU
Peripherals are external devices connected to the computer – printer, keyboard, monitor. The CPU is the core of the computer itself, not a peripheral.
Answer: (C) Some animals are black and some are white.
The statements tell us about dogs (black) and cats (white) only. So some animals (dogs) are black and some (cats) are white. Nothing can be said about all animals or about brown ones.
Answer: (B) G. V. Mavalankar
G. V. Mavalankar was the first Speaker of the Lok Sabha (1952–1956). M. A. Ayyangar succeeded him.
Answer: (C) Mughals
The Delhi Sultanate dynasties – Slave, Khilji, Tughlaq, Sayyid and Lodi – used the title Sultan. The Mughal rulers called themselves Padshah (Badshah), not Sultan.
Answer: (A) Hangul
The Hangul, or Kashmir stag, is a critically endangered red deer found in Dachigam National Park; it is the state animal of J&K.
Answer: (D) Music and mathematics do not go together.
The statement links not appreciating music with becoming a mathematician, implying that music and mathematics do not go together. It says nothing about mathematics being easy, about the majority of mathematicians, or that no musician can ever become a mathematician.
Answer: (D) Chile
Chile won the Copa América Centenario in June 2016, beating Argentina on penalties in the final in the USA.
Answer: (B) Public Sector Undertaking
RailTel Corporation of India, set up in 2000 under the Ministry of Railways, is a Public Sector Undertaking providing telecom and broadband services along railway tracks.
Answer: (B) Cannot be determined
C is Q's mother and P is C's father, so Q is P's grandchild. Q's gender is not given (A being Q's sister says nothing about Q), so grandson or granddaughter cannot be determined.
Answer: (C) Anjali Bhagwat
Anjali Bhagwat is a former world No. 1 Indian rifle shooter. Sudha Singh and Lalita Babar are steeplechase runners.
Answer: (A) Submarine
INS Arihant is India's first indigenous nuclear-powered ballistic missile submarine (SSBN), commissioned in 2016.
Answer: (B) 437
The numbers are (42 + 4)/2 = 23 and (42 − 4)/2 = 19. Their product = 437.
Answer: (D) 32 m
Area = 4b × b = 4b² = 256, so b² = 64 and b = 8 m. Length = 4 × 8 = 32 m.
Answer: (C) the Sun, Moon and Earth are in a direct line
A total solar eclipse occurs at new moon when the Sun, Moon and Earth are in a straight line, and the Moon is close enough to cover the Sun's disc completely.
Answer: (D) Undercurrent
A high tide is a water movement typical of the sea; an undercurrent is a water movement found in a river.
Answer: (A) Thirukural
Thirukkural by Thiruvalluvar is a classic Tamil work. Ratnavali (Harsha), Rajatarangini (Kalhana) and Meghaduta (Kalidasa) are in Sanskrit.
Answer: (D) = × - +
With = × − +: 14 = 9 × 3 − 19 + 6 = 27 − 19 + 6 = 14, which balances.
Answer: (A) 24
Upstream speed = 12 − 3 = 9 km/h and downstream = 15 km/h. Time = 135/9 + 135/15 = 15 + 9 = 24 hours.
Answer: (C) is present in the brain
The hypothalamus is part of the brain, above the pituitary gland. It controls body temperature, hunger, thirst and the pituitary's hormones.
Answer: (D) 42
30 = 6 × 5 (a number times one less than itself). So 7 → 7 × 6 = 42.
Answer: (C) 30 sq. cm
5² + 12² = 13², so this is a right triangle with legs 5 and 12. Area = ½ × 5 × 12 = 30 sq cm.
Answer: (A) 1969
ISRO was founded on 15 August 1969, taking over from INCOSPAR (set up in 1962).
Answer: (C) 24 kmph
Speed of M = 120 km ÷ 2.5 h = 48 km/h. W is half as fast: 24 km/h.
Answer: (D) Railway broadband service
RailWire is the retail broadband service of RailTel Corporation, using its optical fibre network along the railway tracks.
Answer: (A) Australia
The Australia Act 1986 removed the remaining powers of the UK Parliament and courts over Australia, formally ending British legal authority there.
Answer: (A) 341
Each term is n³ − 2: 3³ − 2 = 25, 4³ − 2 = 62, 5³ − 2 = 123, 6³ − 2 = 214. Next: 7³ − 2 = 341.
Answer: (C) 1/2
26/21 ÷ 24/9 = 26/21 × 9/24 = 13/28. So k ÷ 14/13 = 13/28, giving k = 13/28 × 14/13 = 1/2.
Answer: (C) It is based on all observations of data.
The median depends only on the middle value(s) of the ordered data, not on every observation (that is a feature of the mean). So 'it is based on all observations' does not describe the median.