Question

find hcf of 12,15 and20by the prime factorizan method

Answer 1

The correct answer is

22,31,51 and 71 are the greatest powers involved in the prime factors of 12,15 and 21.

so,LCM (12,15,21) =22X31X51X71=420

Answer 2

12=2×2×3

15=5×3

20=2×2×5

Here only 1 is a common factor hence hcf is 1