Number System-Railway Maths Part II

Total Questions: 50

11. The sum of two consecutive multiples of 6 is 66. Find the smaller of these two multiples. [Group D 02/09/2022 (Morning)]

Correct Answer: (b) 30
Solution:

Let the first consecutive number be x
6x + 6(x + 1) = 66
⇒ 12x = 66 - 6 ⇒ 12 x= 60 ⇒ x = 5
Smaller multiple of 6 = 6 * 5 = 30

12. If the number 6484y6 is divisible by 8, then find the least value of y? [Group D 02/09/2022 (Afternoon)]

Correct Answer: (c) 1
Solution:

Divisibility of 8: last 3 digits must be divisible by 8.
6 4 8 4 y 6 → 4y × 6 ÷ 8 4 1 6 ÷ 8 = 52
Least value of y = 1

13. Five times a number is 65. Find the number. [Group D 02/09/2022 (Evening)]

Correct Answer: (c) 13
Solution:

Let the number be x.
5x =65 ⇒ x = 13, Required number = 13

14. How many prime numbers are there between 20 and 80? [Group D 02/09/2022 (Evening)]

Correct Answer: (b) 14
Solution:

Prime numbers between 20 and 80;
23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79.
Hence, there are 14 prime numbers between 20 and 80.

15. When a number is divided by 15, the remainder is 9. What will be the remainder when the same number is divided by 5? [Group D 05/09/2022 (Morning)]

Correct Answer: (d) 4
Solution:

16. Which of the following is the smallest composite number? [Group D 05/09/2022 (Evening)]

Correct Answer: (b) 4
Solution:

Composite numbers are numbers that have more than two factors Factors of 4 = 1, 2 and 4, Therefore, 4 is the smallest composite number.

17. Find the number whose one-third exceeds its one - fifth by 6. [Group D 06/09/2022 (Afternoon)]

Correct Answer: (b) 45
Solution:

18. A two digit number is equal to 7 times the sum of its digits. The number obtained by interchanging the places of the digits is 18 less than the original number. Find the product of the digits of the number. [Group D 06/09/2022 (Evening)]

Correct Answer: (d) 8
Solution:

19. Find the total number of prime numbers less than 50.

Correct Answer: (b) 15
Solution:

Prime number less than 50:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, Total prime numbers = 15

20. Find the value [Group D 06/09/2022 (Evening)]

Correct Answer: (a) -1
Solution: