1. LCM of 2/7 , 3/14 and 5/3 is
A. 45
B. 35
C. 30
D. 25
E. 30
2. About the number of pairs which have 16 as their HCF and 136 as their LCM, the conclusion can be
A. only one such pair exists
B. only two such pairs exist
C. only three such pairs exist
D. no such pair exists
E. many such pairs exist
3. The HCF of two numbers is 12 and their difference is also 12. The numbers are
A.66, 78
B.94, 106
C.70, 82
D.84, 96
E.90,108
4. The HCF of two numbers is 16 and their LCM is 160. If one of the numbers is 32, then the other number is
A.48
B.80
C.96
D.112
E.128
5. HCF of three numbers is 12. If they are in the ratio 1:2:3, then the numbers are
A. 12,24,36
B. 10,20,30
C. 5,10,15
D. 4,8,12
E. 24,36,48
6. Six bells commence tolling together and toll at intervals of 2, 4, 6, 8, 10 and 12 seconds respectively. In 30 minutes, how many times do they toll together?
A. 4
B.10
C.15
D. 16
E. 20
7. The largest natural number which exactly divides the product of any four consecutive natural numbers is :
A. 6
B. 12
C. 24
D. 120
E. 132
8. The number of prime factors in 2222×3333×5555 is
A. 3
B. 1107
C. 1110
D. 1272
E. 1320
9. The traffic lights at three different road crossing change after every 48 sec; 72 sec; and 108 sec., respectively. If they all change simultaneously at 8:20:00 hrs, then they will again change simultaneously at
A. 8:27:12 Hrs
B. 8:27:24 Hrs
C. 8:27:36 Hrs
D. 8:27:48 Hrs
E. 8:27:54 Hrs
10. The greatest number by which if 1657 and 2037 are divided the remainders will be 6 and 5 respectively is
A.127
B.235
C.260
D.305
E.402
11. The total number of prime factors of the product (8)20×(15)24×(7)15 is
A. 59
B. 98
C.123
D. 4
E. 21
12. The HCF and LCM of two numbers are 44 and 264 respectively. If the first number is divisible by 3, then the first number is
A.264
B.132
C. Both a and b
D. 33
E. 45
13. What least number must be subtracted from 1294 so that the remainder when divided 9, 11, 13 will leave in each case the same remainder 6?
A.0
B.1
C.2
D.3
E.4
14.The number of prime factors in the expression (6)10×(7)17×(11)27 is :
A.54
B.64
C.71
D.81
E.100
15. The smallest number which is divisible by 12, 15, 20 and is a perfect square, is
A. 400
B.900
C.1600
D. 3600
E. 4800
16.The least perfect square number which is divisible by 3,4,5,6 and 8 is
A.900
B.1200
C.2500
D.3600
E.4800
17.Three piece of timber 42 m, 49 m and 63 m long have to be divided into planks of the same length. What is the greatest possible length of each plank?
A.7 m
B.14 m
C.42 m
D.63 m
D.69 m
18.The greatest number which can divide 1354, 1866, 2762 leaving the same remainder 10 in each case is :
A.64
B.124
C.156
D.260
E.280
19.Which of the following fractions is the greatest of all?
7/8, 6/7, 4/5, 5/6 ,1/2
A.6/7
B.4/5
.C.5/6
D.7/8
E.1/2
20 LCM of 87 and 145 is :
A. 870
B. 1305
c. 435
D. 1740
E. 1840