Yes, they are relatively prime.
It can be. 27 is relatively prime to 28.
No combination of non-zero even numbers can be relatively prime.
No.
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
No, 28 and 34 are not relatively prime. No pair of even numbers can be relatively prime, as they always share at least one factor (2).
Yes, 4 and 15 are relatively prime.
Yes, they are relatively prime.
Yes, they are relatively prime.
15 is not a prime number, so it can't be a prime factor.
No, they are not.
No they are not.
No. Even numbers can't be relatively prime to each other.
It can be. 27 is relatively prime to 28.
No combination of non-zero even numbers can be relatively prime.
No!
No.