Question

Find the LCM & HCF of the following
integers by applying the prime factorisation
method:
12, 15 & 21​

Answer 1

Prime factorization of 12 : 2 × 2 × 3 = 22 × 3

Prime factorization of 15 : 3 × 5

Prime factorization of 21 : 3 × 7

LCM of 12, 15, and 21 is given as:

LCM(12, 15, 21) = 22 × 3 × 5 × 7 = 4 × 3 × 5 × 7 = 420

HCF of 12, 15, and 21 is given as:

Common factors of the three numbers are: 3

HCF(12, 15, 21) = 3

Answer 2

Answer:

LCM = 420

HCF = 3

Step-by-step explanation:

12 = 2×2×3

15 = 3×5

21 = 3×7

LCM = 3×2×2×5×7

= 12×35

= 420

HCF = 3