2.8

COMMON FACTORS AND HIGHEST COMMON FACTORS (HCF).

EXERCISES.PAPER 1. 1. The first three multiples of 12 are A 2, 3, 4 B C 12, 24, 36 D 6, 12, 18 24, 36, 48 9 54

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Which of the following is a multiple of 27? A 3 B C 39 D

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Which of the following is not a multiple of 3? A 243 B 450 C 1 450 D 1 506 300 , 210 , 150 , 120 The numbers above are multiples of I 5 III 7 A I and II C II and III

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II IV B D

6 13 I and II III and IV

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The 13th multiple of a certain number is 65. What is the number? A 3 B 4 C 5 D 7 Which of the following numbers are common multiples of 12? A 2 and 3 B 4 and 8 C 24 and 50 D 48 and 60 Which of the following is a common multiple of 4 and 9? A 16 B 18 C 36 D 63 The first three common multiples of 2, 3 and 4 are A 6, 12, 18 B 6, 18, 24 C 12, 18, 24 D 12, 24, 36 The following are common multiple s of 2 and 13 except A 22 and 52 B 26 and 52 C 26 and 104 D 52 and 104 Among the following numbers, which are the common multiples of 8 and 24? A 32 and 48 B 16 and 72 C 48 and 72 D 72 and 100 The lowest common multiple of 3, 9 and 15 is A 75 B 60 C 45 D 30

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The lowest common multiple of 8, 16 and p is 48. Which is the possible value of p? A 24 B 28 C 32 D 64 Given that the lowest common multiple of 10, 15 and 20 is x. The value of x is? A 20 B 30 C 40 D 60 60 is the lowest common multiple of A 15 and 24 B 12 and 24 D 12 and 20 1, 2, 3 and 6 are common factors of A 12 and 2 B 12 and 15 C 15 and 18 D 12 and 18 Find all the common factors of 12 and 16. A 1, 2, 4 B 1, 2, 6 C 1, 2, 3, 4 D 1, 2, 4, 8 The highest common factor (HCF) of 27, 45 and 54 is A 3 B 6 C 7 D 9 The highest common factor of m and 34 is 17. What is m? A 51 B 53 C 68 D 75 6 , 18 , 51 , 42 , 35 How many of the numbers above have a highest common factor of 6? A 2 B 3 C 4 D 5 C 12 and 15

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20. Find the product of the lowest common multiple and the highest common factor of 8,12 and 16. A 173 B 181 C 192 D 199

ANSWERS : PAPER 1. 1. 2. 3. 4. 5. C D C B C 6. 7. 8. 9. 10. D C D D C 11. 12. 13. 14. 15. C A B C B 16. 17. 18. 19. 20. A D A B C