1. If the hcf of 8 and k is 1 then their lcm is
A) 8+k B) 8-k C)8k D)8k+1 E)8k-1
2. Which of the following pair is not a co-prime
A) 8, 9 B) 10, 27 C)15, 49 D) 11, 13 E) 15, 27
3. If a,b are co-primes then their hcf is __________
A) 0 B) 1 C)a D)a+b E)ab
4. If a,b are co-primes then their lcm is __________
A) 0 B) 1 C)a D)a+b E)ab
5. If hcf of two numbers is 15 then which of the following cannot be their lcm?
A) 15 B) 45 C)45 D)80 E)90
6. If lcm of two numbers is 240, then which of the following cannot be their hcf?
A) 30 B) 40 C)80 D)100 E)120
7. If z is hcf of x and y then what is the hcf of x/z, y/z?
A) x B) y C)z D)1 E)x+y+z
8. If a, b and c are three numbers such that lcm of a and b is b and lcm of b and c is c, then lcm of a,b and c is____________
A) 1 B) a C)b D)c E) (a+b+c)/3
9. If a,b anc c are three numbers such that hcf of and b is a and hcf of b and c is b, then hcf of a,b and c is __________
A) 1 B) a C)b D)c E) (a+b+c)/3
10. If a, b and c are three numbers such that lcm of a and b is b and lcm of b and c is c, then hcf of a,b and c is____________
A) 1 B) a C)b D)c E) (a+b+c)/3
11. If a,b anc c are three numbers such that hcf of and b is a and hcf of b and c is b, then lcm of a,b and c is __________
A) 1 B) a C)b D)c E) (a+b+c)/3
12. Find the LCM of 12 , 48 and 96.
A) 1 B) 12 C)48 D)96 E) 192
13. Find the HCF of 12 , 48 and 96.
A) 1 B) 12 C)48 D)96 E) 192
14. The HCF of 6/7, 24/35 and 42/49 is
A) 3/245 B) 6/245 C)1/245 D)168/7 E) 1
15. The LCM of 6/7, 24/35 and 42/49 is
A) 3/245 B) 6/245 C)1/245 D)168/7 E) 1
16. The Hcf of two numbers is 15 and their lcm is 90. If one of the number is 30 find the other
A) 450 B) 270 C)180 D)90 E) 45
17. The Hcf of two numbers is 15 and their lcm is 90. If one of the number is 50 find the other
A) 45 B) 27 C)18 D)9 E) Such pair doesn't exist
18. The Hcf of two numbers is 15 and their lcm is 100. If one of the number is 60 find the other
A) 30 B) 25 C)18 D)9 E) Such pair doesn't exist
19. The Hcf of two numbers is 15 and their lcm is 90. If one of the number is 15 find the other
A) 450 B) 270 C)180 D)90 E) Such pair doesn't exist
20. The greatest possible length than can be used to measure exactly the lengths of 24, 56 , 96 is