RRB NTPC Previous Year Questions

1.If three numbers are in the ratio 2:3:5 and the twice their sum is 100. Find the square of the largest of the three numbers.

A) 225
B) 625
C) 125
D) 100

... Answer is B)
Explanation: Given that three numbers are in the ratio 2:3:5 and the twice their sum is 100 Lets assume three numbers are a,b and c therefore, => 2(a + b + c) = 100 2x + 3x + 5x = 50( Given that three numbers are in ratio 2:3:5) =>x = 5 Therefore, largest number would be 25 and it's square would be 625.

2.What is the compound interest on Rs. 48,000 for 2 years at 20 % p.a., if interest is compounded annually? 2(a + b + c) = 100 ,2x + 3x + 5x = 50 ,x = 5

A) 22500
B) 21120
C) 12500
D) 10000

... Answer is B)
Explanation: Amount =P(1 + 100 ) r n where P = Principal r = rate of interest n = number of years Amount after two years = = 69120 Compound Interest = 69120 - 48000 = 21,120 So , the answer would be option b)Rs. 21,120

3.A ladder 20 m long is leaning against a vertical wall. It makes an angle of 30° with the ground. How high on the wall does the ladder reach?

A) 10
B) 62
C) 12.5
D) 10

... Answer is A)
Explanation: From the given information, => P(1 + 100 ) r n 48000(1 + 100 ) 20 2 Sin30 = heightofladder heightofwall 2 = 1 20 heightofwall => height of wall = 10m

4.A piece of cloth costs Rs. 35. If the piece were 4 m longer and each meter were to cost Rs. 1 lesser, then the total cost would remain unchanged. How long is the piece of cloth?

A) 10
B) 14
C) 12
D) 10

... Answer is A)
Explanation: Let the length of cloth be x and price per meter be p. 35 = xp A/c to question , xp = (x + 4)(p -1) x - 4p = -4 x - 140/x = -4 Solving for x , x= 10 So, the answer would be option a)10.

5.Two poles of the height 15 m and 20 m stand vertically upright on a plane ground. If the distance between their feet is 12 m, find the distance between their tops.

A) 11m
B) 12m
C) 13m
D) 14m

... Answer is c)
Explanation:Using Pythagoras theorem , Distance between their tops = = 13m So, the answer would be option c)13 m

6.The simple interest on a certain sum of money invested at a certain rate for 2 years amounts to Rs. 1200 The compound interest on the same sum of money invested at the same rate of interest for 2 years amounts to Rs. 1290. What was the principal?

A) 2200
B) 6250
C) 1250
D) 4000

... Answer is d)
Explanation: Let principal be P and rate of interest be r. Simple interest for 2 years = 1200 Simple interest for 1 year = 600 Difference in compound interest and simple interest = 90 , which is interest earned on the interest of first year. => (600*r)/100= 15 (P×15)/100=600 =>P = 4000 So, the answer would be option d)Rs. 4000.

7.A closed wooden rectangular box made of 1 cm thick wood has the following outer dimensions: length 22 cm, breadth 17 cm, and height 12 cm. It is filled to capacity with cement. What is the volume of the cement in the box?.

A) 2250
B) 3000
C) 1250
D) 1000

... Answer is B)
Explanation: Outer dimensions of the box = 22 cm , 17 cm , 12 cm. Since, Wood is of 1 cm, Inner dimensions are as follows: Inner dimensions : Length = 20 cm Breadth = 15 cm Height = 10 cm Volume = 20 × 15 × 10= 3000 So, the answer would be option b)3000 cu. cm

8.The HCF and LCM of two numbers are 3 and 2730 respectively. If one of the numbers is 78, find the other number.

A) 225
B) 125
C) 105
D) 100

... Answer is c)
Explanation: HCF × LCM = Productoftwonumbers Second number = = 105

9.If P travelled the first half of a journey at 40 km/hr and the remaining distance at 50 km/hr, what is the average speed of his travel?

A) 44.44km/h
B) 62.5
C) 32.5
D) 33.3

... Answer is A)
Explanation:Let d be the distance. Average speed = 44.44 km/hr So, the answer would be option a)44.44 km/hr.

10.Find the LCM of 15, 25 and 29.

A) 2365
B) 3337
C) 2175
D) 2375

... Answer is C)
Explanation: 15 = 3×5 25 = 5×5 29 is a prime number. LCM = 3×5×5×29 =2175 So, the answer would be option c)2175.