## WBCS MAIN PAPER VI : MATHEMATICS - LCM AND HCF

- WBCS Main Examination Paper - VI : 2021
- WBCS Main Examination Paper - VI : 2019
- WBCS Main Examination Paper - VI : 2018
- WBCS Main Examination Paper - VI : 2017
- WBCS Main Examination Paper - VI : 2016
- WBCS Main Examination Paper - VI : 2015
- WBCS Main Examination Paper - VI : 2014

1.If x is a prime number, the LCM of x and (x + 1) is

(A) (x+1)2 (square) (B) x2(square) (C) x(x+1)/2 (C) x(x+1)

2.HCF of the fractions 2/3 , 4/5 and 6/7 is

(A) 481105 **(B) 2/105 **(C) 24/105 (D) 1/105

3.The HCF of two numbers is 4 and LCM is 520. If one of the numbers is 52 the other number is then

**(A) 40 **(b) 42 (C) 52 (D) 50

4.If the ratio of three numbers are 3:4:5 and their LCM is 1200, then the smallest number is

(A) 80 **(B) 60 **(C) 120 (D) 100

5. The G.C.M. of two numbers is 17 and their product is 6936. The no. of pairs of such numbers is

(A) 4 **(B) 2 **(C) 3 (D) 5

6. The sum of two numbers is 150 and their H.C.F. is 15. The number of possible pairs is

**(A) 2** (8) 3 (C) 4 (D) 5

1.The ratio of two numbers is 3 : 4 and their L.C.M. is 180. Find the numbers.

**(A) 45, 60** (B) 40, 25 (C) 50, 30 (D) 30, 60

1.The product of two numbers is 1320 and their H.C.F. is 6. The L.C.M. of number is

**(A) 220** (B) 1314 (C) 1326 (D) 7920

1.If *a* is a prime number, then the L.C.M. of a and (a + 1) is

**(A) a (a+1)** (B) a2(square) (C) (A+1)2(square) (D) A(A+1)/2

2.The H.C.F. and L.C.M. of two numbers x and y are respectively 3 and 105. If x+ y = 36, then 1/x + 1/y = ?

**(A) **4/36 (B) 1/35 (C) 35 (D) 3 /5

3.The H.C.F. of two numbers is 12 and their difference is also 12. The numbers are

(A) 66, 76 (B) 70, 82 (C) 94, 108 **(D) 84, 96**

4.The H.C.F. of 0.54, 1.8 and 7.2 is

**(A) 0.18** (B) 1.8 (C) 0.018 (D) 18

1.If the ratio of three numbers is 3 : 4 : 5 and their LCM is 1200, then the smaller number is :

**(A) 60** (B) 80 (C) 100 (D) 120

2.The product of two co-primes is 117 ; their L.C.M. should be :

(A) 1 (B) 117 **(C) equal to their H.C.F.** (D) Cannot be calculated

1.The H.C.F. of three numbers is 12. If they are in the ratio 1 : 2 : 3, then the numbers are

(A) 6, 12, 18 (B) 10, 20, 30 **(C) 12, 24, 36** (D) 24, 48, 72

2.If two numbers are in the ratio 5 : 7 and their L.C.M. is 315, then their product is

(A) 2358 (B) 2385 (C) 2538 **(D) 2835**

3.The product of two Co-primes is 117. Their L.C.M. should be

(A) 1 **(B) 117** (C) equal to their H.C.F. (D) Cannot be calculated

1. The H.C.F. and L.C.M. of three numbers are 6 and 420. If two numbers be 12 and 30, the third number will be -

(A) 21 (B) 18 **(C) 42** (D) 70

2.The HCF of two numbers is 145 and their LCM is 2175. If one of the number is 725, the other number is-

(A) 290 **(B) 435** (C) 5 (D) none of the above