Question

(i) Rakesh has jersey number 31 and Ramesh got 93 on his jersey. Check whether 31 and 93 are co-primes or not. What will be their HCF if they are co-primes?

(ii) Sachin got 17 marbles and Sourav got 84. Check whether the above numbers given are composite numbers or not?

Answer 1

(i) $31=1\times 31$ so the factors of 31 are 1 and 31
$93=31\times 3$ . So the factors of 93 are 3 and 31.

Two natural numbers are co-primes if they do not have a common factor other than 1.
Therefore, 31 and 93 are not co-prime numbers.
The HCF of two co-prime numbers is 1.

(ii) The factors of 17 are 1 and 7
Similarly, the factors of 84 are 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42 and 84.

Here, 17 is not a composite number as its factors are 1 and 17 itself. So, it is a prime number.
But 84 is a composite number because it has more than 2 factors.