RRB NTPC 2021 PYQs

Question 1

In Δ ABC, ∠A : ∠B :∠C = 2 : 3 : 5, then find the measure of the supplementary angle of ∠A.

Accepted Answer

The sum of angles in a triangle is 180°. Given ratio 2:3:5, ∠A = (2/10)*180° = 36°. The supplementary angle of ∠A is 180° - 36° = 144°.

Question 2

A tank has two inlets, A and B, which can fill it in 15 hours and 20 hours, respectively. An outlet C can empty the full tank in 12 hours. If A, B and C are opened together when the tank is empty, then in how much time will the tank be filled?

Accepted Answer

Calculate the combined filling rate (1/15 + 1/20 - 1/12) which is 1/30. Therefore, the tank will be filled in 30 hours.

Question 3

27% of 250 - 0.02% of 1000 is equal to:

Accepted Answer

Calculate 27% of 250 as (27/100)*250 = 67.5. Calculate 0.02% of 1000 as (0.02/100)*1000 = 0.2. Subtract 0.2 from 67.5 to get 67.3.

Question 4

Where is the headquarters of UNICEF situated?

Accepted Answer

UNICEF, the United Nations Children's Fund, has its global headquarters located in New York City, USA. This is a direct factual recall question.

Question 5

A man bought 2 articles for Rs. 3,000 each. He sold one article at 10% profit and another at 5% profit. Find the total percentage profit he earned.

Accepted Answer

Calculate profit on each article: 10% of 3000 = 300, 5% of 3000 = 150. Total profit = 450. Total cost = 6000. Percentage profit = (450/6000) * 100 = 7.5%.

Question 6

A rectangular field is 16 meters long and 12 meters wide. A barbed fence has to be drawn on three sides of the field leaving one side open along the width. What is the cost of fencing at the rate of 25 paise per cm?

Accepted Answer

The fence covers two lengths and one width: (16+16+12)m = 44m. Convert to cm: 4400 cm. Cost = 4400 cm * 0.25 Rs/cm = Rs. 1100.

Question 7

The National Informatics Centre (NIC) was established in:

Accepted Answer

The National Informatics Centre (NIC) was established in 1976. It is a premier technology organization under the Ministry of Electronics and Information Technology.

Question 8

Mahatma Gandhi's first major public appearance in India after returning from South Africa was at the opening of the ________ in February 1916.

Accepted Answer

Mahatma Gandhi's first significant public speech in India after returning from South Africa was at the inauguration of Banaras Hindu University in February 1916.

Question 9

The Book - The Test of My Life - was written by-

Accepted Answer

The book 'The Test of My Life: From Cricket to Cancer and Back' is the autobiography of Indian cricketer Yuvraj Singh, detailing his battle with cancer.

Question 10

What is the average of 4.2, 3.8 and 7.6?

Accepted Answer

Sum the numbers (4.2 + 3.8 + 7.6 = 15.6) and divide by the count (3). 15.6 / 3 = 5.2.

Question 11

A and B can finish a work in 9 days, B and C can finish it in 12 days and A and C can finish it in 18 days. In how many days can A, B and C finish the work together?

Accepted Answer

Calculate individual work rates: (A+B)'s 1/9, (B+C)'s 1/12, (A+C)'s 1/18. Summing these gives 2(A+B+C)'s rate. Halve it for (A+B+C)'s rate, then take the reciprocal for total days.

Question 12

A bank provides a loan at the rate of 5% per annum to a trader on an amount of Rs.12,50,000 for 5 years. The simple interest to be paid is:

Accepted Answer

Use the simple interest formula: SI = (P * R * T) / 100. Substitute P=12,50,000, R=5, T=5. Calculate (1250000 * 5 * 5) / 100 = 3,12,500.

Question 13

For every 18 eggs that Noori buys, three eggs turn out to be rotten. At the same rate, how many good eggs will Noori have if she buys 690 eggs?

Accepted Answer

For every 18 eggs, 3 are rotten, so 15 are good. The good egg ratio is 15/18 = 5/6. For 690 eggs, good eggs = (5/6) * 690 = 575.

Question 14

The  given shows the number of students in a hostel speaking different languages:LanguagesHindiEnglishMarathiTamilBengaliTotalNumber of Students2522129472Which language is spoken by atleast 1 out of 3 students residing in the hostel?

Accepted Answer

Total students are 72. One-third of students is 72/3 = 24. Hindi is spoken by 25 students, which is more than 24. Thus, Hindi is the correct answer.

Question 15

Simplify.‌46‌+‌34‌×‌32−637−‌34×(34−6)

Accepted Answer

Follow BODMAS: first solve the parenthesis (34-6=28). Then perform multiplications (34×32=1088, 34×28=952). Finally, add and subtract from left to right: 46 + 1088 - 637 - 952 = 4.

Question 16

Which Navratna company is fondly called 'Vizag steel'?

Accepted Answer

Rashtriya Ispat Nigam Limited (RINL) is a Navratna company based in Visakhapatnam, Andhra Pradesh, and is commonly known as 'Vizag Steel'.

Question 17

If α and β are the zeroes of the polynomial x2– 5x + m such that α – β = 1, then what will be the value ofm.

Accepted Answer

Given α+β = 5 and α-β = 1. Solving these equations gives α=3, β=2. Since αβ = m, substitute the values to get m = 3*2 = 6.

Question 18

In the given△KMN, PQ is parallel to MN. If‌KPPM=‌413and KN = 20.4 cm, find KQ

Accepted Answer

By Basic Proportionality Theorem, KP/PM = KQ/QN. Given KP/PM = 4/13. So KQ/QN = 4/13. Total KN = KQ + QN. Let KQ = 4x and QN = 13x. Then 4x + 13x = 17x = 20.4 cm. So x = 1.2 cm. Thus, KQ = 4 * 1.2 = 4.8 cm.

Question 19

Which number among the given options does not belong to the following series?4, 7, 13, 26, 49, 97

Accepted Answer

The pattern is (previous number * 2) - 1. So, 4*2-1=7, 7*2-1=13, 13*2-1=25. Thus, 26 is incorrect; it should be 25.

Question 20

On which river is Idukki Dam built?

Accepted Answer

The Idukki Dam is a significant arch dam located in Kerala, India. It is constructed across the Periyar River, which is one of the longest rivers in Kerala.