RRB NTPC 2021 PYQs

Question 1

If the length of side of a square is increased by 10%, what is the percentage increase in its area?

Accepted Answer

Let original side be 's'. New side is 1.1s. Original area s². New area (1.1s)² = 1.21s². Percentage increase = ((1.21s² - s²)/s²) * 100 = 21%.

Question 2

If cot A =‌1√3, then what is the value of‌1−cos‌⁡2A1‌+‌cos‌⁡2A?

Accepted Answer

Given cot A = 1/√3, so A = 60°. The expression 1−cos⁡2A / 1+cos⁡2A simplifies to tan²A. Substitute A = 60°, so tan²60° = (√3)² = 3.

Question 3

Ifsin‌⁡(A+B)=\;{{√{3}}}/{2} \;	extand"‌‌"‌cos⁡(A−B)=‌√32then which of the following will be possible values of A and B?

Accepted Answer

From sin(A+B) = √3/2, A+B = 60°. From cos(A-B) = √3/2, A-B = 30°. Solving these two linear equations gives A = 45° and B = 15°.

Question 4

The Japanese leg of the Tokyo 2021 Olympic torch relay have been scheduled to start from _______ in March 2021.

Accepted Answer

The Tokyo 2021 Olympic torch relay was scheduled to begin from Fukushima, symbolizing recovery from the 2011 earthquake and tsunami.

Question 5

Name the only bird that can fly backwards.

Accepted Answer

Hummingbirds are unique among birds for their ability to fly backward, hover, and fly upside down due to their specialized wing structure and flight muscles.

Question 6

If sin A =‌12and cos B =‌12then find A + B.

Accepted Answer

Given sin A = 1/2, so A = 30°. Given cos B = 1/2, so B = 60°. Therefore, A + B = 30° + 60° = 90°.

Question 7

In how many years will a sum of Rs. 1,600 amount of Rs. 2,116 at 15% compound interest?

Accepted Answer

Use the compound interest formula A = P(1 + R/100)^n. Substitute values: 2116 = 1600(1 + 15/100)^n. Simplify to (2116/1600) = (1.15)^n. Since 2116/1600 = 1.3225 and (1.15)^2 = 1.3225, n = 2 years.

Question 8

A businessman purchase 20 articles whose cost is equal to the selling price of 15 articles. The profit or loss percentage of the businessman is:

Accepted Answer

Let CP of 1 article be Re 1. Then CP of 20 articles = Rs 20. SP of 15 articles = Rs 20. SP of 1 article = 20/15 = 4/3. Profit = SP - CP = 4/3 - 1 = 1/3. Profit % = (1/3)/1 * 100 = 33.33%.

Question 9

Eminent Social reformer and Women’s education activist Pandita Ramabai Sarasvati was a great scholar of ______

Accepted Answer

Pandita Ramabai Sarasvati was a renowned scholar of Sanskrit. The title 'Pandita' was bestowed upon her for her proficiency in the language.

Question 10

When was the State Reorganisation Commission formed in India?

Accepted Answer

The State Reorganisation Commission was constituted in 1953 to recommend the reorganisation of states on linguistic lines. Its report led to the States Reorganisation Act, 1956.

Question 11

Which of the following has been written by Munshi Premchand?

Accepted Answer

Munshi Premchand is a renowned Hindi writer. 'Sevasadan' is one of his famous novels, depicting social issues. The other options are works by different prominent authors.

Question 12

Which of the following was stated in the 'Gandhi-Irwin Pact' signed in March 1931?

Accepted Answer

The Gandhi-Irwin Pact, signed in 1931, primarily aimed to end the Civil Disobedience Movement. This was a key condition for Gandhi's participation in the Second Round Table Conference.

Question 13

In a certain code language, 'Car have wheels' is written as '@ mu #', 'Wheels are red' is written as 'Su bc mu', 'I have red car' is written as '7 @ Su #'. Which among the following is the code for 'Wheels car' in that language?

Accepted Answer

Compare the given statements to find common words and their corresponding codes. 'Wheels' is common in statement 1 and 2, so 'mu' is its code. 'Car' is common in statement 1 and 3, so '#' is its code. Thus, 'Wheels car' is 'mu #'.

Question 14

_______ is a well known constellation that can be seen in the evening. This constellation is also known as 'the Hunter'.

Accepted Answer

The constellation known as 'the Hunter' is Orion. It is one of the most recognizable constellations visible in the night sky.

Question 15

Which organisation launched a military communication satellite for Indian Air Force called- GSAT-7A in December 2018?

Accepted Answer

ISRO is India's primary space agency responsible for satellite launches. GSAT-7A, a military communication satellite, was launched by ISRO in December 2018.

Question 16

On 22April 2019, Ministry of AYUSH signed a MoU with which of the following organisations to promote research and education in traditional system of medicine and its integration with modern science?

Accepted Answer

The Ministry of AYUSH signed an MoU with CSIR on April 22, 2019, to promote research and education in traditional medicine and integrate it with modern science.

Question 17

Programming language Java was developed by _______.

Accepted Answer

James Gosling is widely recognized as the father of the Java programming language. He developed it at Sun Microsystems in the mid-1990s.

Question 18

When was the first Passenger train run in India?

Accepted Answer

The first passenger train in India ran on April 16, 1853, from Bori Bunder (Mumbai) to Thane, covering a distance of 34 km.

Question 19

The value so obtained on adding the sum and the difference of the numbers 3.03 and 2.05, is:

Accepted Answer

Let the numbers be A and B. The sum is A+B, and the difference is A-B. Adding these gives (A+B) + (A-B) = 2A. So, 2 * 3.03 = 6.06.

Question 20

A water tank is made of an aluminum sheet 3 cm thick. The tank is open at the top. Its external dimensions are 1.36 m, 1.06 m, and height 0.83 m. What is the cost of painting the inner surface of the tank at 50 paise per 100 sq. cm?

Accepted Answer

Calculate inner dimensions by subtracting twice the thickness from length/breadth and once from height. Find the inner surface area (open top). Convert to sq. cm and multiply by the cost per sq. cm.