RRB NTPC 2021 PYQs

Question 1

Bananas are bought at the rate of 3 for Rs. 2 and sold at the rate of 2 for Rs. 3. Find the percentage gain.

Accepted Answer

To find the percentage gain, calculate the cost price (CP) and selling price (SP) of one banana. CP = 2/3, SP = 3/2. Profit = SP - CP = 3/2 - 2/3 = 5/6. Percentage gain = (Profit/CP) * 100 = (5/6) / (2/3) * 100 = 125%.

Question 2

Who was the first Speaker of the Lok Sabha?

Accepted Answer

G. V. Mavalankar served as the first Speaker of the Lok Sabha from 1952 to 1956. This is a direct factual recall question.

Question 3

The sum of two numbers is 25 and their difference is 15. The ratio of the numbers is:

Accepted Answer

Let the numbers be x and y. x + y = 25 and x - y = 15. Adding equations gives 2x = 40, so x = 20. Then y = 5. The ratio is 20:5 = 4:1.

Question 4

The Rourkela Steel Plant started with the inauguration of first blast furnace by the then Preside of India in:

Accepted Answer

The Rourkela Steel Plant's first blast furnace was inaugurated by the then President of India, Dr. Rajendra Prasad, in 1959.

Question 5

The least number which should be added to 4707 so that the sum is exactly divisible by 4, 5, 6 and 8 is:

Accepted Answer

Find the LCM of 4, 5, 6, and 8, which is 120. Divide 4707 by 120 to get a remainder of 3. Subtract this remainder from 120 to find the number to add: 120 - 3 = 117. However, 117 is not an option. The question asks for the least number to be added. The next multiple of 120 after 4707 is 4800. So, 4800 - 4707 = 93.

Question 6

If 16 sec2θ – 40 sec θ + 25 = 0 and θ is an acute angle, then what will be the value of tan θ?

Accepted Answer

Recognize the given equation as a perfect square (4secθ - 5)² = 0. Solve for secθ = 5/4. Use the identity tan²θ = sec²θ - 1 to find tanθ = 3/4.

Question 7

Which British physicist was awarded the Nobel Prize in Physics in 1906 for his work on discovery of electrons ?

Accepted Answer

J.J. Thomson discovered the electron and was awarded the Nobel Prize in Physics in 1906 for this groundbreaking work.

Question 8

The value of a machine depreciates at the rate of 10% per annum. If its present value is Rs. 1,62,000, what was the value (in Rs.) of the machine 2 years ago?

Accepted Answer

Let the value 2 years ago be P. Present value = P * (1 - 0.10)^2. So, 162000 = P * (0.9)^2 = P * 0.81. Thus, P = 162000 / 0.81 = 200000.

Question 9

Which type of storage device is a Hard Disc?

Accepted Answer

Hard disks are non-volatile storage devices used for long-term data storage, making them a classic example of secondary storage.

Question 10

Given below are few statements and their respective codes in a particular language:Horse are Cat – XYTCat is Blue – TMZBlue is Cloud – ZMSWhich of the given options will be the code for the following statement in that language:Blue Cat is Cloud-?

Accepted Answer

By comparing the given statements, 'Cat' is common in the first two, so its code is 'T'. 'Blue' is common in the last two, so its code is 'Z'. 'is' is common in the second and third, so its code is 'M'. 'Cloud' is 'S'. Thus, Blue Cat is Cloud is ZTMS.

Question 11

How many world heritage sites have been protected by UNESCO as of June 2020?

Accepted Answer

As of June 2020, UNESCO had designated 1121 World Heritage Sites globally. This is a direct factual recall question.

Question 12

If the denominator of a rational number is of the form 2n5m, where n and m are non-negative integers, then what will be the  decimal expansion of the number?

Accepted Answer

A rational number has a terminating decimal expansion if and only if its denominator, in simplest form, has prime factors only 2 and 5.

Question 13

Name the Kalvari class submarine launched in Mumbai in Nov 2020.

Accepted Answer

INS Vagir, the fifth submarine of the Kalvari class, was launched in November 2020 at Mazagon Dock Shipbuilders in Mumbai. This is a direct factual recall question.

Question 14

A, B and C entered into partnership. A invested 3 times as much as B and B invested‌23times of what C invested. At the end of the year the total profit was Rs.6,600. B's share in the profit is:

Accepted Answer

Establish the investment ratio A:B:C as 6:2:3. The total ratio sum is 11. B's share is (2/11) * 6600, which equals Rs. 1200.

Question 15

A shopkeeper gives 20% discount on MRP. Joginder buys a suitcase from the shop, at an additional discount of 20% on the reduced price. If the MRP of the suitcase is Rs. 1,200, then find the purchasing price paid by Joginder.

Accepted Answer

First discount: 20% of 1200 = 240. Price after first discount = 1200 - 240 = 960. Second discount: 20% of 960 = 192. Final price = 960 - 192 = 768.

Question 16

An observer 1.5 m tall is standing 28.5 m away at the same level as the foot of a tower. If angle of elevation of the observer watching the top of the tower is 45 degrees then what is the height of the tower?

Accepted Answer

The horizontal distance is 28.5m. With an elevation angle of 45 degrees, the height above the observer's eye level is 28.5m (tan 45 = 1). Add the observer's height (1.5m) to get the total tower height: 28.5 + 1.5 = 30m.

Question 17

Which famous person identified with the slogan- "Do or Die"?

Accepted Answer

Mahatma Gandhi gave the 'Do or Die' call during the Quit India Movement in 1942, urging Indians to achieve independence or die trying.

Question 18

What is the full form of CLI in Computer terminology?

Accepted Answer

CLI stands for Command Line Interface. It is a text-based interface used for interacting with a computer program or operating system.

Question 19

(√7+√9)(√7−√9)is equal to:

Accepted Answer

This is in the form (a+b)(a-b) = a² - b². Here a=√7 and b=√9. So, (√7)² - (√9)² = 7 - 9 = -2.

Question 20

Select the combination of letters that when sequentially placed in the blanks will create a repetitive pattern.a_bc_a_bcda_ccd_bcd_

Accepted Answer

The pattern is 'aabc/cdda/abbc/cdd'. Filling the blanks with option 3 (a, d, b, b, a, d) completes this repeating sequence, forming a logical and consistent series.