# LCM-HCF TNPSC Group 2 2A Questions

## LCM-HCF MCQ Questions

1.

If LCM of "a" and "b" is a and LCM of "b" and "c" is b, then what is the LCM of "c" and "a".

Group 1 - 2019

A.

a

B.

b

C.

c

D.

abc

A. a

2.

Find the LCM of 3(a-1), 2(a-1)2, (a2-1)

Group 4 - 2019

A.

(a+1)2(a+1)

B.

(a-1)2(a+1)

C.

6(a-1)(a+1)2

D.

6(a-1)2(a+1)

D. 6(a-1)2(a+1)

3.

The GCD and LCM of two polynomials are x+1 and x4 - 1 respectively. If one of the polynomials is x2 + 1, find the other one.

Group 1 - 2019

A.

x3 - 1

B.

(x + 1)(x2 - 1)

C.

x2 + x -1

D.

x2 - x + 1

B. (x + 1)(x2 - 1)

4.

Find the LCM of a3b4, ab5 and a2b7

Group 4 - 2016

A.

a7b3

B.

a3b7

C.

a2b5

D.

ab5

B. a3b7

5.

Product of two positive number ,is 34560. The LCM is sixty times of its GCD. Then the difference of LCM and GCD is

Group 1 - 2017

A.

1416

B.

1424

C.

1460

D.

1464

A. 1416

6.

The product of two numbers is 1600 and their H.C.F. is 5, the L.C.M. of the number is

Group 2 - 2018

A.

320

B.

1605

C.

1595

D.

8000  