RRB NTPC 2021 PYQs

Question 1

If‌3x2y=‌4872then‌xyin its lowest term is:

Accepted Answer

Simplify 48/72 to 2/3. Then, 3x/2y = 2/3. Cross-multiply to get 9x = 4y, so x/y = 4/9.

Question 2

How many triangles are there in the given diagram?

Accepted Answer

Count individual triangles (6). Then count triangles formed by combining two smaller triangles (2). Finally, count the largest triangle (1). Total 6+2+1=9.

Question 3

The marks obtained by 7 students in a class in mathematics are 43, 44, 65, 41, 53, 65 and 62. The mode of the data is:

Accepted Answer

The mode is the value that appears most frequently in a data set. In the given data, 65 appears twice, which is more than any other number.

Question 4

Taxol is extracted from which plant?

Accepted Answer

Taxol, an important anti-cancer drug, is primarily extracted from the bark of the Pacific Yew tree. This is a direct factual recall question.

Question 5

A statement is given followed by two arguments. Decide which of the arguments is/are strong with respect to the statement.Statement:Life expectancy of Indians is increasingArguments:I. Yes, People are getting better medical facilities.Ii. Yes, People are doing more physical exercises now.

Accepted Answer

Both improved medical facilities and increased physical exercise directly contribute to better health and longer lifespans. Therefore, both arguments provide strong reasons for the increasing life expectancy.

Question 6

Simplify.17 × 8 - 6 + [(27 - 3) ÷ 6 - 4]

Accepted Answer

Follow BODMAS: first solve the bracket (27-3=24, then 24/6=4, then 4-4=0). Then multiply 17x8=136. Finally, 136-6+0 = 130.

Question 7

With the success of the anti-satellite (ASAT) test in 2019, with which other countries did India join the league?

Accepted Answer

India became the fourth country to successfully test an ASAT missile in 2019, joining the US, Russia, and China in this elite group.

Question 8

If we increase 50% of the numerator and 80% of the denominator of a fraction, then what fraction of the original will be the new fraction?

Accepted Answer

Let the original fraction be x/y. New numerator is 1.5x and new denominator is 1.8y. The new fraction is (1.5x)/(1.8y) = (15/18)(x/y) = (5/6)(x/y).

Question 9

The International Court of Justice is located in ________.

Accepted Answer

The International Court of Justice (ICJ) is the principal judicial organ of the United Nations, and its headquarters are located in The Hague, Netherlands.

Question 10

If X = 32× 2, Y = 23× 3 and Z = 32× 22then the L.C.M. of XY, YZ, ZX is:

Accepted Answer

First, calculate XY, YZ, ZX. Then, for LCM, take the highest power of each prime factor present in XY, YZ, and ZX. The LCM is 2^5 * 3^4 = 32 * 81 = 2592.

Question 11

50% of a number is 21 less than‌45th of that number. Find the number.

Accepted Answer

Let the number be x. Set up the equation: 0.5x = (4/5)x - 21. Simplify to 0.5x = 0.8x - 21. Solve for x: 0.3x = 21, so x = 70.

Question 12

Which architect has designed the India Gate in New Delhi?

Accepted Answer

India Gate, a prominent war memorial in New Delhi, was designed by the renowned British architect Sir Edwin Lutyens. He also played a key role in designing much of New Delhi.

Question 13

15 male employees or 20 female employees of a company can complete a project in 26 days. How long will 30 male employees and 12 female employees together take to complete the project?

Accepted Answer

Equate work done by men and women: 15M = 20W, so 3M = 4W. Convert 30M + 12W to women-equivalent: 40W + 12W = 52W. If 20W take 26 days, then 52W take (20*26)/52 = 10 days.

Question 14

Where is the Sambhar Lake situated?

Accepted Answer

Sambhar Lake, India's largest inland salt lake, is located in the state of Rajasthan. It is a significant wetland.

Question 15

Which is Satyajit Ray's famous film about the decline of the aristocratic zamindari style of living?

Accepted Answer

Satyajit Ray's 'Jalsaghar' (The Music Room) vividly portrays the decline of an aristocratic zamindar and his opulent lifestyle, making it the correct answer.

Question 16

The perimeter of a right triangle is 60 cm and its hypotenuse is 26 cm. Find the area of the triangle.

Accepted Answer

Let sides be a, b, 26. Perimeter a+b+26=60, so a+b=34. By Pythagoras, a²+b²=26²=676. (a+b)²=a²+b²+2ab => 34²=676+2ab => 1156=676+2ab => 2ab=480 => ab=240. Area = 0.5 * ab = 0.5 * 240 = 120 cm².

Question 17

How manyodd numbers are preceded by the number 4in the following series?2 6 6 3 4 5 2 4 9 8 6 4 3 4 8 2

Accepted Answer

Identify pairs where '4' is immediately followed by an odd number. The pairs are 4-5, 4-9, and 4-3. Thus, there are 3 such instances.

Question 18

The number between 6000 and 7000 that is divisible by each of 12, 21, 32 and 18 is:

Accepted Answer

Find the LCM of 12, 21, 32, and 18, which is 2016. Multiply the LCM by an integer (k) such that the result falls between 6000 and 7000. 2016 * 3 = 6048.

Question 19

If three cubes whose edges measure 3 cm, 4 cm and 5 cm respectively, are melted to form a single cube, then find the edge of the new cube.

Accepted Answer

Calculate the sum of volumes of the three cubes (3³+4³+5³ = 27+64+125 = 216 cm³). The new cube's volume is 216 cm³, so its edge is the cube root of 216, which is 6 cm.

Question 20

The Red Fort of Agra was founded by which Mughal Emperor?

Accepted Answer

Akbar commissioned the construction of the Agra Fort, also known as the Red Fort of Agra, between 1565 and 1573. It served as his primary residence.