HCF and LCM
Top questions
See all →- What is the least number which, when divided by 12, 15, 20 and 54, leaves a remainder of 8 in each case? Answer: A. 548 Answer: (A) 548 LCM(12, 15, 20, 54) = 540. Required number = 540 + 8 = 548 . 1
- The HCF of two numbers is 15 and their LCM is 420. If one of the numbers is 105, what is the other number? Answer: D. 60 Answer: (D) 60 Product of two numbers = HCF × LCM. Other number = 15 × 420/105 = 60 . Check: HCF(60, 105) = 15 and LCM = 420. 1
- Two numbers are in the ratio 3 : 4 and their LCM is 180. What is the sum of the two numbers? Answer: D. 105 Answer: (D) 105 Let the numbers be 3k and 4k (HCF k). LCM = 12k = 180, so k = 15. Numbers are 45 and 60; sum = 105. 1
- Three bells ring at intervals of 12, 18 and 30 minutes. If they ring together at 9:00 a.m., when will they next ring together? Answer: B. 12:00 noon Answer: (B) 12:00 noon LCM(12, 18, 30) = 180 minutes = 3 hours. 9:00 a.m. + 3 h = 12:00 noon. 1
- The HCF and LCM of two numbers are 12 and 360 respectively. If one of the numbers is 72, what is the other? Answer: A. 60 Answer: (A) 60 Product of the numbers = HCF × LCM. Other number = 12 × 360/72 = 60 . 1