HCF and LCM – (Railway Maths Part VII)

Total Questions: 50

11. The LCM and HCF of two numbers are 60 and 3, respectively . If the first number is 12, then the second number is: [RRB NTPC 05/04/2021 (Morning) ]

Correct Answer: (c) 15
Solution:

12. The product of two numbers is 270. If their LCM is 90, then their HCF is: [RRB NTPC 05/04/2021 (Morning) ]

Correct Answer: (d) 3
Solution:

13. What is the least number, which, when divided by 45 and 55 leaves a remainder of 3 in each case? [RRB NTPC 06/04/2021 (Morning) ]

Correct Answer: (b) 498
Solution:

14. The ratio of the HCF to the LCM of the numbers √64 and 16 is: [RRB NTPC 06/04/2021 (Morning) ]

Correct Answer: (a) 1 : 2
Solution:

15. The HCF of 15, 25 and 42 is: [RRB NTPC 06/04/2021 (Evening) ]

Correct Answer: (d) 1
Solution:

16. Find the smallest number, which when divided by 35,40 and 60 leaves a remainder 7 in each case. [RRB NTPC 07/04/2021 (Morning) ]

Correct Answer: (c) 847
Solution:

17. The LCM of 248 and 868 is 1736. The HCF of the same two numbers is: [RRB NTPC 07/04/2021 (Morning) ]

Correct Answer: (a) 124
Solution:

18. Three pieces of aluminum rod of different lengths, 44 cm, 22 cm and 55 cm respectively, are given to a boy. He has to cut them into rods of same length such that no aluminum waste is left. The maximum length (in cm) of such rod will be: [RRB NTPC 07/04/2021 (Evening) ]

Correct Answer: (d) 11 cm
Solution:

HCF of 44, 22, 55 = 11 cm

19. The greatest number that divides 155 and 307 leaving remainders 5 and 7, respectively, is: [RRB NTPC 07/04/2021 (Evening) ]

Correct Answer: (c) 150
Solution:

155 - 5 = 150
307 - 7 = 300
HCF of 150 and 300 = 150

20. Find the least number that when divided by 9, 8, 10 and 12 leaves a remainder of 3 in each case. [RRB NTPC 08/04/2021 (Morning) ]

Correct Answer: (c) 363
Solution:

LCM of 9, 8, 10, 12 = 360
Remainder = 3
So the required number = 360 + 3 = 363