Yes, they are relatively prime.
hcf(10, 21) = 1 ⇒ 10 & 21 relatively prime hcf(12, 54) = 6 ⇒ 12 & 54 not relatively prime hcf(15, 27) = 3 ⇒ 15 & 27 not relatively prime hcf(21, 38) = 1 ⇒ 21 & 38 relatively prime
Yes.
No. For example: 9 and 27 are both odd but not relatively prime (they both have the factor 3).
Yes, e.g. 3 and 5 are relatively prime, 27 (33) and 25 (52) are relatively prime...
No, they are not relatively prime. They both have 3 as a common factor. 15 = 5 x 3 27 = 3 x 3 x 3
No because they are both composite numbers
No, neither of them are.
One number, by itself cannot be relatively prime - or otherwise. Relative primality is a property of two (or more) numbers.
They are all prime numbers except for 15 21 25 and 27 which are composite numbers
No, they are not relatively prime.
Yes, they are relatively prime.