Question

1. Which of the following is a pair of co-primes? b. 18,25 d. 41,35
​

Answer 1

Both pairs i.e. option (b) and option (d) are co-primes

Explanation :

Co-primes are numbers with no factor common among them other than 1 .

In pair 1, we have the factors of 18 as 1,2,3,6,9,18 and that of 25 1,5,25 and since their highest common factor is 1 ,thus they are co-primes

Similarly,

In pair 2 , the factors of 41 is 1 and 41 itself and that of 35 is 1,5 and 35 and cause their greatest common factor is 1 , therefore they are co-primes.

Answer 2

18 and 25 form a pair of co-primes.

41 and 35 form a pair of co-primes.

Explanation:

Co-primes are two numbers that share no common positive integer factors other than 1. In other words, their only common factor is 1. These two numbers can be prime or composite, just as long as their only common factor 1.

The factors of 18 are 1, 2, 3, 6, 9 and 18.

The factors of 25 are 1, 5 and 25.

As the only common factor of 18 and 25 is 1, this means that 18 and 25 form a pair of co-primes.

The factors of 41 are 1 and 41.

The factors of 35 are 1, 5, 7 and 35.

As the only common factor of 41 and 35 is 1, this means that 41 and 35 form a pair of co-primes.