Find the HCF of the following by Prime factorisation,
a) 72,54, 27
b) 24, 16, 36 do this please with full solutions

here

72, 54, 27 are divisible by 3, to check divisibility by 3 we have to add the digits.

dividing all three digits by 3 we get :

3 x 24 =  72

3 x 18 = 54

3 x 9 = 27

now we have 24, 18, 9

check divisibility by 2, but no, it is not possible. 2 is not divisible by 5 so we take 3, yes three is divisible

24, 18, 9

3 x 8 = 24

3 x 6 = 18

3 x 3 = 9

so now we have 8,6,3

this is neither divisible by 2 or 3 so now we multiply 3 x 3

= 9

second answer is 4