Explanation:
Finding the HCF of the given pairs of numbers,
HCF (7,36) =7
HCF (36,25) =1
HCF (35,29) =1
HCF (63,81) =9
As the HCF of 36 & 25 and 35 & 29 are 1, these are co-prime numbers.
The other two pairs do not have the HCF as 1, thus they are not co-prime numbers.
Final Answer :
Options B and C are correct, that is,
The co-prime numbers from the given pairs are (B) 36 and 25 and (C) 35 and 29.
