Practice Questions on LCM & HCF

01) Four runners started running simultaneously from a point on a circular track. They took 200 sec, 300 sec, 360 sec and 450 sec to complete one round. After how much time do they meet at the starting point for the first time?

          a) 1800 sec

          b) 3600 sec

          c) 2400 sec

          d) 4800 sec

02) The greatest number of four digits which when divided by 3, 5, 7, 9 leaves remainder 1, 3, 5, 7 respectively is:

          a) 9763

          b) 9764

          c) 9766

          d) 9765

03) L.C.M o 2/3, 4/9, 5/6 is

          a) 8/27

          b) 20/3

          c) 10/3

          d) 20/27

04) The LCM of two prime numbers x and y, (x>y) is 161. The value of (3y-x):

          a) -2

          b) -1

          c) 1

          d) 2

05) What is the LCM of 120 and 450?

          a) 2400

          b) 1800

          c) 3600

          d) 4800

 

06) What is the largest two digit number which is exactly divisible by both 6 and 5? [SSC MTS Exam 03/10/2017, Shift III]

          a) 90

          b) 92

          c) 60

          d) 96

07) When 12, 16, 18, 20 and 25 divide the least number x, the remainder in each case is 4 but x is divisible by 7. What is the digit at the thousand’s place in x?

          a) 5

          b) 8

          c) 4

          d) 3

08) The number of factors of 3600 is

          a) 45

          b) 44

          c) 43

          d) 42

09) Let x be the least number which when divided by 15, 18, 20 and 27, the remainder in each case is 10 and x is a multiple of 31. What least number should be added to x to make it a perfect square?

          a) 39

          b) 37

          c) 43

          d) 36

10) Which among the following numbers is exactly divisible by 11, 13 and 7?

          1. 624643 2. 624624 3. 624635 4. 624646

          a) 1

          b) 2

          c) 3

          d) 4