Question

The ratio between the LCM and HCF of 5,15,20 is :
(a) 9:1
(b) 4:3
(c) 11:1
(d) 12:1

Answer 1

Given:

5,15,20

To find:

The ratio between the LCM and HCF of 5,15,20

Solution:

1) The LCM of 5,15,20 is

• 5 = 5

• 15 = 3×5

• 20 = 2×2×5

• LCM[5,15,20] = 2×2×3×5 = 60

2) The HCF of the given numbers is 5

• LCM : HCF = 60 : 5

•                   = 12 :  1

Option D is correct.

The ratio between the LCM and HCF of 5,15,20 is 12:1 .

Answer 2

12:1 is the ratio between lcm and hcf of 5, 15, 20