RRB NTPC 2020 PYQs

Question 1

If interest is compounded annually, a sum of Rs 25,000 becomes Rs 36,000 after 2 years. The rate of interest is:

Accepted Answer

Use the compound interest formula A = P(1 + R/100)^T. Substitute given values: 36000 = 25000(1 + R/100)^2. Simplify to (6/5)^2 = (1 + R/100)^2, so 6/5 = 1 + R/100. Solving for R gives 20%.

Question 2

If '+' is replaced by '-', '×' is replaced by '+' and '-' by '×'. then28+(5×7)−‌96will be equal to:

Accepted Answer

By substituting the given mathematical operators into the expression and applying the BODMAS rule, we evaluate the equation to find the correct value of 10.

Question 3

When was the first session of Indian National Congress held?

Accepted Answer

The first session of the Indian National Congress was held in December 1885 in Bombay. It marked a significant event in India's freedom struggle.

Question 4

The value of‌√54‌×‌√125√24×√45is:

Accepted Answer

Simplify each square root: √54 = 3√6, √125 = 5√5, √24 = 2√6, √45 = 3√5. Substitute these into the expression: (3√6 × 5√5) / (2√6 × 3√5). Cancel common terms (√6 and √5) to get (3 × 5) / (2 × 3) = 15/6 = 2.5.

Question 5

Sita took an auto from her home in Andheri (A) to go to her college in Fatehpuri (F). Rather than continuing straight on the direct road to the college that had no turns, the auto driver took a diversion after 10 km and tumed right at Bandra (B) crossing, then at Colaba T- point (C) after 8 km turned left, again after covering 12 km turned left at Dalhousi Building (D) and soon after 8 km turned right at Elphinston point (E) and after covering 4 km reached Fatehpuri (F). Had the auto driver taken the direct route how much less distance would Sita have actually travelled between the starting point and the destination?

Accepted Answer

The auto driver's path forms a rectangle (8km x 12km) with an initial 10km and final 4km. Total distance covered is 10+8+12+8+4 = 42 km. The direct route is 10+12+4 = 26 km. The difference is 42 - 26 = 16 km.

Question 6

From the top of a cliff 25 m high, the angle of elevation of the top of a tower is found to be equal to the angle of depression of the foot of the tower. Find the height of the tower.

Accepted Answer

Let cliff height be h. If angle of elevation and depression are equal (θ), then tower height H = h + h = 2h. So, H = 2 * 25 = 50 m.

Question 7

Which of the following country was the host of the United Nations Environment Program - 'World Environment Day, 2020'?

Accepted Answer

Colombia, in partnership with Germany, hosted World Environment Day 2020. The theme was biodiversity, highlighting its critical importance.

Question 8

What is the smallest number which when increased by 3 is divisible by 27, 35, 25 and 21?

Accepted Answer

Find the LCM of 27, 35, 25, and 21, which is 4725. Since the number increased by 3 is divisible, subtract 3 from the LCM to get the answer: 4725 - 3 = 4722.

Question 9

The horizontal distance between two towers is 40√3 m. The angle of depression of the top of the first tower when seen from the top of the second tower is 30°. If the height of the second tower is 130 m, find the height of the first tower.

Accepted Answer

Let h be the height difference. tan(30°) = h / (40√3). So, h = 40√3 * (1/√3) = 40 m. Height of first tower = 130 - 40 = 90 m.

Question 10

The value of 5 sin 14° sec 76° + 3 cot 15° cot 75° + 2 tan 45° is:

Accepted Answer

Use complementary angle identities: sec 76° = cosec 14° and cot 75° = tan 15°. Also, tan 45° = 1. Substitute these to simplify the expression to 5(1) + 3(1) + 2(1) = 10.

Question 11

Which of the following isNOTa part of the circulatory system?

Accepted Answer

The circulatory system comprises the heart, blood, and blood vessels (arteries, veins, capillaries). The large intestine is part of the digestive system.

Question 12

Which of the following is an example of Footloose industry?

Accepted Answer

Footloose industries are not tied to specific raw materials or markets. Computer chip manufacturing fits this description due to its low material weight and high value.

Question 13

A sum of Rs 5,000 is invested at 10% simple interest per annum. In how many years will the amount of interest become Rs. 1,500?

Accepted Answer

Use the simple interest formula: I = PRT/100. Substitute I=1500, P=5000, R=10. Solve for T: 1500 = (5000 * 10 * T) / 100, which gives T = 3 years.

Question 14

The sum of two numbers is 20 and their difference is 2.5. Ratio of these numbers will be:

Accepted Answer

Let the numbers be x and y. x + y = 20 and x - y = 2.5. Adding equations gives 2x = 22.5, so x = 11.25. Then y = 20 - 11.25 = 8.75. The ratio x:y is 11.25:8.75, which simplifies to 9:7.

Question 15

What is the theme of World Environment Day 2019?

Accepted Answer

World Environment Day 2019 focused on 'Beat Air Pollution' as its theme. This global event aimed to raise awareness and encourage action against air pollution.

Question 16

Which of the following two countries of South America are landlocked?

Accepted Answer

Paraguay and Bolivia are the only two landlocked countries in South America. All other options include countries with coastlines.

Question 17

If 'A' means ‘+’, ‘S’ means ‘-’, ‘M’ means ‘×’, ‘D’ means ‘÷’, ‘B’ means ‘(’ and ‘F’ means ‘)’, then solve the following expression:B700A110S90FDB9M10S10F

Accepted Answer

Substitute the symbols: (700+110-90) ÷ (9×10-10). Simplify inside parentheses: (810-90) ÷ (90-10) = 720 ÷ 80 = 9.

Question 18

A, B and C can complete a job in 40 days, 60 days and 80 days respectively. All the three worked together but A left 11 days and B left 8 days before the completion of work. In how many days, the entire work will be completed?

Accepted Answer

Calculate total work as LCM of days (240 units). Find daily efficiencies. Assume work finishes in 'x' days. A works (x-11) days, B works (x-8) days, C works x days. Sum of work done equals 240. Solve for x.

Question 19

Ifx∕y=4∕5, then‌5x+7y5x−7y+‌6x+4y7x−8yis equal to:

Accepted Answer

Divide numerator and denominator of both fractions by 'y'. Substitute x/y = 4/5 into the expressions. Simplify each fraction and then add them to get the final result.

Question 20

In the given figure, value of x is:

Accepted Answer

The sum of angles in a triangle is 180°. So, x + 50° + 70° = 180°. Solving this gives x = 180° - 120° = 60°.