RRB NTPC CBT-I Official Paper (Held On: 30 Dec 2020 Shift 1) · 100 questions. Try each question, then open its answer.
Answer: (C) 35 m
The longest pole is the room's diagonal: √(30² + 15² + 10²) = √(900 + 225 + 100) = √1225 = 35 m.
Answer: (C) \((abc)^\frac{1}{2}\)
With edges l, b, h: a = lb, b = bh, c = hl, so abc = (lbh)². Volume = lbh = (abc)^½.
Answer: (C) Karnataka
Karnataka is India's largest gold producer, mainly from the Hutti and Kolar regions.
Answer: (B) 6.25%
One year's growth from Rs 1600 to Rs 1700 is Rs 100, i.e. 100/1600 = 6.25% per annum.
Answer: (D) Jammu & Kashmir
The Zojila Tunnel, giving all-weather road access between Srinagar and Leh under the Zoji La pass, is in Jammu & Kashmir/Ladakh.
Answer: (B) input
A trackball – a ball rolled to move the pointer – is an input device.
Answer: (D) 6891.59775
6202.5 + 620.25 + 62.025 + 6.2025 + 0.62025 = 6891.59775.
Answer: (D) UVTCVGIA
Each letter of VIARAIL moves 2 places forward to give XKCTCKN. Applying +2 to STRATEGY gives UVTCVGIA.
Answer: (A) 5
The sum of the first n odd numbers is n². 1 + 3 + 7 + 9 + 11 + 13 is missing 5; adding it gives 49 = 7².
Answer: (A) Dynamic Host Configuration Protocol
DHCP is the Dynamic Host Configuration Protocol, which automatically assigns IP addresses to devices on a network.
Answer: (B) Kothari Commission
The Sarkaria, Punchhi and Rajamannar Commissions examined Centre–State relations. The Kothari Commission (1964–66) was on education.
Answer: (D) 16
Primes below 55: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53 – that is 16.
Answer: (A) syncline
When rock layers fold, the downward (trough) folds are synclines and the upward (arch) folds are anticlines.
Answer: (C) Curator
A gardener looks after a garden; a curator looks after a museum.
Answer: (D) 20
In the first triangle the centre number is (top + bottom-left) ÷ 5 = (37 + 43) ÷ 5 = 16. Applying the same to the second: (47 + 53) ÷ 5 = 20. (The third triangle does not follow this neatly; the official RRB answer is 20.)
Answer: (B) 36
The figure is a 3 × 3 grid with 4 horizontal and 4 vertical lines. A rectangle needs 2 of each: C(4, 2) × C(4, 2) = 6 × 6 = 36.
Answer: (B) 1024
1 kilobyte = 2¹⁰ = 1024 bytes.
Answer: (D) Aditya-L1
Aditya-L1 is ISRO's mission to study the Sun's corona and solar wind from the L1 Lagrange point; it was launched in September 2023.
Answer: (D) Birmingham
The 2022 Commonwealth Games were held in Birmingham, England.
Answer: (A) 32
x − 0.25x = 0.75x = 24, so x = 32.
Answer: (B) Sardar Vallabhbhai Patel
Sardar Vallabhbhai Patel led the Bardoli Satyagraha of 1928, after which the women of Bardoli gave him the title 'Sardar'.
Answer: (B) 12.5%
Coefficient of variation = SD/mean × 100 = 5/40 × 100 = 12.5%.
Answer: (A) Silicon
Silicon is a metalloid, with properties between metals and non-metals. Bromine is a non-metal; lead and gold are metals.
Answer: (D) Lord Hardinge
The Royal Commission on the Public Services in India (Islington Commission) was set up in 1912, during Lord Hardinge II's viceroyalty (1910–1916).
Answer: (D) 300 kg
Zinc is 6 of 20 parts. 6 parts = 90 kg, so 1 part = 15 kg and the whole = 20 × 15 = 300 kg.
Answer: (D) Ethylene
Ethylene (ethene) is polymerised to make polyethylene (polythene), the most common plastic.
Answer: (B) Shudraka
Mricchakatika ('The Little Clay Cart'), a Sanskrit drama, was written by Shudraka.
Answer: (B) TSRQ
Each letter is replaced by its opposite letter in the alphabet (A↔Z, B↔Y, …): ABCD → ZYXW. So GHIJ → TSRQ.
Answer: (B) 105°
In triangle ABC, ∠ACB = 180° − 30° − 50° = 100°, so ∠ECD = 80°. In triangle ECD, ∠CED = 180° − 80° − 25° = 75°. So ∠AED = 180° − 75° = 105°.
Answer: (A) Spinal cord
The spinal cord carries impulses between the brain and the body and is the centre of reflex actions.
Answer: (A) 15
Avinash does 1/20 a day; Bhuvnesh and Chaman together do 1/30 + 1/60 = 1/20. In every 3 days: 3/20 + 1/20 = 1/5 of the work. The whole takes 5 × 3 = 15 days.
Answer: (A) -40
(4 + 2 − 4 + 3) = 5; (1 + 56) ÷ 19 = 3; [(3 + 5 − 4) + (17 − 36)] = 4 − 19 = −15. So 5 + 3 × (−15) = −40.
Answer: (A) Telangana
Telangana, carved out of Andhra Pradesh on 2 June 2014, became India's 29th state.
Answer: (A) N. K. Singh
N. K. Singh, a former IAS officer and Rajya Sabha MP, chaired the Fifteenth Finance Commission (2017).
Answer: (C) \(\frac{4}{35}\)
After round 1: 2/3 left. After round 2: 2/3 × 2/5 = 4/15. After round 3: 4/15 × 3/7 = 4/35 of the original.
Answer: (B) 3(x - y)(y - z)(z - x)
If a + b + c = 0 then a³ + b³ + c³ = 3abc. Here (x − y) + (y − z) + (z − x) = 0, so the sum = 3(x − y)(y − z)(z − x).
Answer: (B) Dachigam National Park
Dachigam National Park near Srinagar, home of the Hangul (Kashmir stag), is in Jammu & Kashmir.
Answer: (D) George Lamaitre
Belgian physicist-priest Georges Lemaître proposed the 'primeval atom' theory in 1927–31, later called the Big Bang theory.
Answer: (D) 1991
Disinvestment of public sector enterprises began in 1991–92 as part of the economic reforms.
Answer: (D) 6
3 men = 6 boys, so 1 man = 2 boys. The work = 3 × 20 = 60 man-days. 6 men + 8 boys = 10 men, so 60/10 = 6 days.
Answer: (B) \(\frac{23}{99}\)
0.2323… (23 repeating) = 23/99.
| Formal Learners | Boys | 39 |
|---|---|---|
| Girls | 52 | |
| Informal Learners | Boys | 65 |
| Girls | 78 | |
| Illiterates | Boys | 143 |
| Girls | 169 |
Answer: (A) 7 : 11 : 24
Formal = 39 + 52 = 91, informal = 65 + 78 = 143, illiterates = 143 + 169 = 312. Dividing by 13: 7 : 11 : 24.
Answer: (B) Bogibeel Bridge
The 4.94 km Bogibeel bridge over the Brahmaputra near Dibrugarh, opened in December 2018, is India's longest rail-cum-road bridge.
Answer: (A) Education
SATH-E (Sustainable Action for Transforming Human capital – Education) is NITI Aayog's project to transform school education in partner states.
Answer: (D) 56
The terms are n(n + 1): 1×2, 2×3, …, 6×7 = 42. Next: 7 × 8 = 56.
Answer: (B) Pradhan Mantri Jan Dhan Yojana
Pradhan Mantri Jan Dhan Yojana entered the Guinness World Records for opening 1.8 crore bank accounts in a single week in August 2014.
Answer: (C) Qutb-ud-din Aibak
Qutb-ud-din Aibak founded the Slave (Mamluk) dynasty of the Delhi Sultanate in 1206.
Answer: (C) Kerala
Kerala has a unicameral legislature. Karnataka, Maharashtra and Telangana have Legislative Councils.
Answer: (C) GAGAN
GAGAN (GPS Aided GEO Augmented Navigation), by ISRO and the Airports Authority of India, is India's satellite-based augmentation system.
Answer: (D) Dismiss
Disobey is the opposite of obey; dismiss is the opposite of appoint.
Answer: (A) 0
The product includes cos 90° = 0, so the whole product is 0.
Answer: (A) Rs. 34,500
In year 3, bank A pays 8.5% and bank B 10%. The difference of 1.5% on Rs 23,00,000 = Rs 34,500.
Answer: (D) Arctic ocean and Pacific Ocean
The Bering Strait, between Russia and Alaska, connects the Arctic Ocean with the Pacific Ocean.
Answer: (C) 200
First three years: 150 + 100 + 250 = 500. Last three: 100 + 300 + 300 = 700. Difference = 200.
Answer: (C) 80%
Fall = 84500 − 16900 = 67600, and 67600/84500 × 100 = 80%.
Answer: (D) P
Boys facing north, west to east: A, E, C, D, B – C in the centre, D between C and B, and B three seats from E. Girls opposite: T opposite B with S to T's right, so S and T face D and B; P sits between Q and R, opposite E. So P is opposite E.
Answer: (D) Vardhamana
Mahavira, the 24th Jain Tirthankara, was born Vardhamana.
Answer: (C) 0
cos 168° = −cos 12° and cos 96° = −cos 84°, so the four terms cancel in pairs: the sum is 0.
Answer: (C) \(\frac{19}{32}\)
36.1/102.4 = 361/1024, so the square root is 19/32.
Answer: (B) reptiles
Reptiles have a backbone and are vertebrates. Molluscs, arachnids and insects are invertebrates.
Answer: (A) Kerala
The 2018 Nipah virus outbreak occurred in Kozhikode and Malappuram districts of Kerala.
Answer: (C) 1% Loss
When two articles are sold at the same price, one at x% gain and the other at x% loss, the net result is a loss of x²/100 % = 100/100 = 1%.
Answer: (A) 3 cm
The height from the apex bisects the base: half-base = 4 cm, so height = √(5² − 4²) = 3 cm.
Answer: (D) 8
9.25 ÷ 1.125 ≈ 8.2, so about 8 loaves.
Answer: (C) Plato
'The Republic', a dialogue on justice and the ideal state, was written by the Greek philosopher Plato.
Answer: (D) Abhidharma kosha
The Abhidharmakosha by Vasubandhu is an ancient Buddhist philosophical text. Vishnu Purana is Hindu, and Raghuvamsham and Ritusamhara are Kalidasa's poems.
Answer: (B) 10
After the changes: 28 − (5 + 7) × 9/6 = 28 − 12 × 1.5 = 28 − 18 = 10.
Answer: (A) 4722
LCM(27, 35, 25, 21) = 3³ × 5² × 7 = 4725. The number is 3 less: 4722.
Answer: (B) 9 : 7
The numbers are (20 + 2.5)/2 = 11.25 and (20 − 2.5)/2 = 8.75. Ratio 11.25 : 8.75 = 9 : 7.
In the given figure, value of x is:
Answer: (B) 60°
ABCDE is a pentagon with interior angles adding to 540°. ∠A = 90°, ∠B = 180° − 65° = 115°, ∠C = 180° − 80° = 100° and ∠D = 115°, so ∠E = 540° − 420° = 120°. x is supplementary to it: x = 60°.
Answer: (B) Aunt
A is C's uncle (brother of C's father B), and D is A's wife, so D is C's aunt.
Answer: (B) Coal
Water, solar and wind energy are renewable; coal is a non-renewable fossil fuel.
Answer: (B) Green plant
Water, sunlight and soil are abiotic (non-living). A green plant is a living, biotic component.
Answer: (C) 83.75 km
Moving in opposite directions, their separation grows at 30 + 3.5 = 33.5 km/h. In 2.5 h: 83.75 km.
Answer: (C) 52/123
1 + 4 − 3 + 65 = 67. (2 + 63)/13 = 5 and 65 + 7 − 19 = 53, giving 265. 19 − 195 = −176. Numerator = 67 + 265 − 176 = 156, and 156/369 = 52/123.
Answer: (A) HysIS
HysIS (Hyperspectral Imaging Satellite), launched by PSLV-C43 in November 2018, is India's first advanced hyperspectral Earth-observation satellite.
Answer: (A) \(\frac{1}{36}\)
There are 36 equally likely outcomes and only (6, 6) gives a sum of 12. Probability = 1/36.
Answer: (C) Ramanujacharya
Ramanujacharya (11th–12th century) founded Vishishtadvaita (qualified non-dualism).
Answer: (B) Supply stabilisation of TOP crops (Tomato Onion Potato)
Operation Greens (2018) aims to stabilise the supply and prices of tomato, onion and potato (TOP crops).
Answer: (A) Everyone desires pleasure.
Calling pleasure 'desirable' assumes that it is something everyone desires.
Answer: (C) Apsara
Apsara, which went critical at Trombay on 4 August 1956, was India's (and Asia's) first nuclear research reactor.
Answer: (C) Pretoria
South Africa has three capitals: Pretoria (administrative), Cape Town (legislative) and Bloemfontein (judicial).
Answer: (B) Paris
The OECD (Organisation for Economic Co-operation and Development) is headquartered in Paris.
Answer: (A) Metazoa
Metazoa – multicellular animals – make up Kingdom Animalia. Protozoa are single-celled organisms placed in Kingdom Protista, and Choanozoa are their single-celled relatives.
Answer: (D) Rs. 156
At an 8% loss, CP = 138/0.92 = Rs 150. For a 4% gain, SP = 150 × 1.04 = Rs 156.
Answer: (A) All voters are loyalists.
All voters are citizens and all citizens are loyalists, so all voters are loyalists.
Answer: (D) Incomplete information may cause harm.
The proverb warns that partial knowledge can mislead; it rests on the idea that incomplete information may cause harm.
Answer: (C) All artists are cartoonists.
With the shaded regions removed, the only artists left are in the region common to all three circles, so all artists are cartoonists. Some cartoonists remain outside the artists circle, and the remaining artists are also billionaires, so the other options are false.
B.
C.
D.
Answer: (A) A
A mirror image reverses the order of letters and flips each letter: ENCOURAGEMENT becomes TNEMEGARUOCNE with every letter mirrored – option 1.
Answer: (C) 112
The code is the sum of letter positions: PENINSULA = 16 + 5 + 14 + 9 + 14 + 19 + 21 + 12 + 1 = 111. DICHOTOMY = 4 + 9 + 3 + 8 + 15 + 20 + 15 + 13 + 25 = 112.
Answer: (C) 121
These are squares of odd numbers: 1², 3², 5², 7², 9², so the next is 11² = 121.
B.
C.
D.
Answer: (C) C
Plates and bowls are both crockery but different from each other: two separate circles inside one big circle – option 3.
Answer: (A) YUP
Each letter is replaced by its opposite (A↔Z, E↔V, J↔Q). So BFK → YUP.
Answer: (D) 5
Doctors who are surgeons but not general practitioners lie in the overlap of the Surgeons and Doctors circles outside the GP circle – 5.
Answer: (B) 163
The terms increase alternately by 10 and 20: 13, 23, 43, 53, 73, 83, 103, 113, 133, 143, so the next is 143 + 20 = 163.
Answer: (A) 12 : 11
Highest (Kolkata) = 1,20,000 and lowest (Mumbai) = 1,10,000. Ratio = 12 : 11.
Answer: (D) No amphibians are horses.
All horses are mammals and no mammal is an amphibian, so no horse is an amphibian – equivalently, no amphibians are horses.
Answer: (A) Compass
Beaker, test tube and dropper are laboratory glassware for liquids. A compass is a drawing or direction instrument.
A.
B.
C.
D.
Answer: (A) A
As per the official RRB key, option 1 completes the pattern. (The dot counts 3, 6, 9 would suggest 12 next, which no option has, so the official answer is taken here.)
| 14 | 12 | 10 | 8 |
|---|---|---|---|
| 10 | 8 | 2 | 4 |
| 8 | 14 | 6 | 16 |
| 12 | 18 | 14 | ? |
Answer: (D) 20
As per the official RRB key, the missing number is 20. (No single simple row or column rule fits every cell of the printed matrix, so the official answer is taken here.)
