RRB NTPC 2021 PYQs

Question 1

Where was the First experimental satellite telecommunication earth station set up in 1967 in India?

Accepted Answer

India's first experimental satellite telecommunication earth station was established in 1967 at Ahmedabad, Gujarat. This marked a significant step in the country's space communication efforts.

Question 2

Select the number from among the given options that will come next in the following series.4, 16, 40, ?

Accepted Answer

The differences between consecutive terms are 12 (16-4) and 24 (40-16). The next difference should be 36 (12+12). So, 40 + 36 = 76. Wait, the correct answer is 88. Let's re-examine. The differences are 12, 24. This is 12*1, 12*2. The next difference should be 12*3 = 36. So 40+36 = 76. This is not 88. Let's try another pattern. The differences are 12, 24. The difference of differences is 12. So the next difference should be 24+12 = 36. So 40+36 = 76. Still not 88. Let's try another pattern. The differences are 12, 24. The next difference should be 48 (24*2). So 40+48 = 88. This matches the answer. The pattern is: add 12, then add 24, then add 48. Each added number is double the previous added number.

Question 3

A  __________ is a homogeneous mixture of two or more substances.

Accepted Answer

A solution is defined as a homogeneous mixture of two or more substances. This is a fundamental concept in chemistry.

Question 4

What is the value of the following expression?(243)2÷ (27)2× 6 ÷ 18

Accepted Answer

Simplify the expression using order of operations (BODMAS/PEMDAS). (243/27)^2 * 6 / 18 = 9^2 * 1/3 = 81 * 1/3 = 27.

Question 5

Which of the following isNOTa part of a personal computer?

Accepted Answer

CPU, ROM, and RAM are internal components of a personal computer. USB (Universal Serial Bus) is an interface standard for connecting external peripherals, not an internal part.

Question 6

Mohan is twice as good as Kamlesh and together, they finish a task in 22 days. Mohan alone can finish the task in:

Accepted Answer

Mohan's efficiency is twice Kamlesh's. If Kamlesh takes 'x' days, Mohan takes 'x/2' days. Their combined work rate is 1/x + 2/x = 3/x. Since they finish in 22 days, 3/x = 1/22, so x = 66. Mohan takes x/2 = 33 days.

Question 7

The value of‌(−12)5(−‌12)4+‌(−18)(−‌14)is

Accepted Answer

Simplify the expression using exponent rules: $(-1/2)^5(-1/2)^4 = (-1/2)^9 = -1/512$. Then, $(-1/8)(-1/4) = 1/32 = 16/512$. Adding these gives $-1/512 + 16/512 = 15/512$. Oh, wait. Let's re-evaluate. $(-1/2)^5(-1/2)^4 = (-1/2)^{5+4} = (-1/2)^9 = -1/512$. And $(-1/8)(-1/4) = 1/32$. The question is likely a typo and should be $(-1/2)^5 / (-1/2)^4 + (-1/8)(-1/4)$. If it is division, then $(-1/2)^5 / (-1/2)^4 = -1/2$. Then $-1/2 + 1/32 = -16/32 + 1/32 = -15/32$. If the original question is correct, then the answer is $15/512$. Given the options, there must be a typo in the question. Assuming the question meant $(-1/2)^5 \div (-1/2)^4 + (-1/8)(-1/4)$, then it simplifies to $(-1/2) + (1/32) = -16/32 + 1/32 = -15/32$. None of the options match. Let's assume the question meant $(-1/2)^5 	imes (-1/2)^{-4} + (-1/8)(-1/4)$. This would be $(-1/2)^{5-4} + 1/32 = -1/2 + 1/32 = -15/32$. Still no match. Let's assume the question meant $(-1/2)^5 	imes (-1/2)^4 + (-1/8) 	imes (-1/4)$. This is $(-1/2)^9 + 1/32 = -1/512 + 16/512 = 15/512$. Still no match. Let's assume the question meant $(-1/2)^5 \div (-1/2)^4 + (-1/8) \div (-1/4)$. This would be $(-1/2) + (1/8 	imes 4/1) = -1/2 + 1/2 = 0$. This matches option 1. So the question must have intended division for both parts. Let's proceed with this assumption. First part: $(-1/2)^5 \div (-1/2)^4 = (-1/2)^{5-4} = -1/2$. Second part: $(-1/8) \div (-1/4) = (-1/8) 	imes (-4/1) = 4/8 = 1/2$. Adding them: $-1/2 + 1/2 = 0$.

Question 8

Which newspaper did Mahatma Gandhi start in South Africa?

Accepted Answer

Mahatma Gandhi started the newspaper 'Indian Opinion' in South Africa in 1903. It was a crucial tool for his satyagraha movement.

Question 9

When did the Simon Commission arrive in India?

Accepted Answer

The Simon Commission, appointed in 1927, arrived in India in 1928 to study constitutional reforms. This led to widespread protests.

Question 10

The law that permitted widows to remarry (Hindu Widows' Remarriage Act) was passed in the year:

Accepted Answer

The Hindu Widows' Remarriage Act was passed in 1856. Ishwar Chandra Vidyasagar played a pivotal role in its enactment.

Question 11

Which of the following statements is true?

Accepted Answer

A complex number is of the form a + bi. A real number 'a' can be written as a + 0i, thus every real number is a complex number.

Question 12

In an election the votes cast for two candidates were in the ratio 2 ∶ 9. If the successful candidate received 984321 votes, find the total voters polled.

Accepted Answer

The ratio is 2:9. The successful candidate received 9 parts, which is 984321 votes. So, 1 part = 984321/9 = 109369. Total votes = (2+9) parts = 11 parts = 11 * 109369 = 1203059.

Question 13

Two trains starting at the same time in opposite directions from two stations 200 km apart meet each other at a distance of 110 km from one of the stations. What is the ratio of their speed?

Accepted Answer

When trains meet, time taken is equal. The ratio of speeds is equal to the ratio of distances covered. Distances are 110 km and (200-110) = 90 km. So, the ratio is 110:90 or 11:9.

Question 14

'Glove' is related to 'Hand' in the same way as 'Cap' is related to '________'.

Accepted Answer

A glove is worn on the hand. Similarly, a cap is worn on the head. This is a functional relationship of an item to the body part it covers.

Question 15

To commemorate his victory over Gujarat, Akbar built 'Gate of Magnificence' the highest gateway of India at Fatehpur Sikri. What is another name for this gateway?

Accepted Answer

The 'Gate of Magnificence' built by Akbar at Fatehpur Sikri to commemorate his victory over Gujarat is famously known as Buland Darwaza.

Question 16

A, B and C can complete a piece of work in 6, 12 and 24 days respectively. They all together will complete the work in:

Accepted Answer

A's 1-day work = 1/6, B's = 1/12, C's = 1/24. Combined 1-day work = 1/6 + 1/12 + 1/24 = (4+2+1)/24 = 7/24. Total days = 24/7 = 3 3/7 days.

Question 17

Find the value of√2025.

Accepted Answer

To find the square root of 2025, notice it ends in 5, so its root must end in 5. Since 40²=1600 and 50²=2500, the root is 45.

Question 18

Consider the given statements and decide which of the given assumptions does not follow from the given statements:Some Grass is Green.All Green is Red.

Accepted Answer

From 'Some Grass is Green', 'Some Green is Grass' follows. From 'Some Grass is Green' and 'All Green is Red', 'Some Grass is Red' follows. 'All Red is Green' is a converse error.

Question 19

The ratio of the number of females to that of male employees in a small company is 2 ∶ 3. If the number of male employees in the company is 90, then the total number of employees working in the company is:

Accepted Answer

Given male employees are 90, and the ratio of females to males is 2:3. So, 3 parts = 90, meaning 1 part = 30. Females = 2 parts = 60. Total employees = 60 + 90 = 150.

Question 20

The Southernmost tip of Indian territory is ______.

Accepted Answer

Indira Point, located in the Nicobar Islands, is the southernmost point of Indian territory. Kanyakumari is the southernmost point of mainland India.