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Home › Grade7 › Grade 7 Olympiad › Math Olympiad-Grade-7 › HCF, LCM & Factorisation › HCF and LCM Worksheet-5

HCF and LCM Worksheet-5

HCF and LCM Worksheet-5

 

  1. Four different electronic devices make a beep after every 30 minutes, 1 hour, hour and 1 hour 45 minutes respectively. All the devices beeped together at 12 noon. They will again beep together at :

(a) 12 midnight                             (b) 3 a.m.

(c) 6 a.m.                                        (d) 9 a.m.

 

  1. A, B and C start at the same time in the same direction to run around a circular stadium. A completes a round in 252 seconds, B in 308 seconds and C in 198 seconds, all starting at the same point. After what time will they meet again at the starting point?

(a) 26 minutes 18 seconds         (b) 42 minutes 36 seconds

(c) 45 minutes                              (d) 46 minutes 12 seconds

 

  1. Find the Greatest Common Factor of 15 and 25.

(a) 10                  (b) 5                    (c) 15                   (d) 25

 

  1. Find the Greatest Common Factor of 21, 56 and 63.

(a) 14                   (b) 3                    (c) 7                    (d) 9

 

  1. Find the Greatest Common Factor or 16, 32 and 60.

(a) 8                    (b) 16                  (c) 6                    (d) 4

 

  1. Find the Greatest Common Factor of 18, 27 and 90.

(a) 9                    (b) 10                  (c) 18                  (d) 6

 

  1. Find the Greatest Common Factor of 39 and 65.

(a) 9                    (b) 12                  (c) 13                   (d) 16

 

  1. Two numbers have a greatest common factor equal to 6 and a least common multiple equal to 36. If one of the numbers is 12, find the other number.

(a) 24                  (b) 15                  (c) 18                  (d) 45

 

  1. Find the Greatest Common factor of 42, 63 and 105.

(a) 21                   (b) 7                    (c) 14                   (d) 9

 

  1. Jerry has 42 apples, 56 pears and 98 oranges. He wants to pack each type of fruit in separate boxes with maximum number of fruits in each box. He also wants equal number of fruits in each basket with no fruit left. How many fruits will there be in each box?

(a) 28                  (b) 14                  (c) 36                  (d) 22

 

  1. Which set of numbers will have a Greatest Common factor equal to 16?

(a) 48, 96, 145                               (b) 24, 40, 64

(c) 50, 560, 140                            (d) 48, 80, 112

 

  1. Find the Greatest Common factor of 36, 54 and 126.

(a) 12                  (b) 18                  (c) 27                  (d) 9

 

  1. Find the least common multiple of 12 and 80.

(a) 280               (b) 280               (c) 224               (d) 240

 

  1. Find the LCM of 9, 10 and 45.

(a) 90                  (b) 60                 (c) 54                  (d) 95

 

  1. Find the LCM of 54 and 90.

(a) 180               (b) 270               (c) 216                (d) 121

 

Answer Key:

(1)-(d); (2)-(d); (3)-(b); (4)-(c); (5)-(d); (6)-(a); (7)-(c); (8)-(c); (9)-(a); (10)-(b); (11)-(d); (12)-(b); (13)-(d); (14)-(a); (15)-(b)