Question

The two numbers which have only 1 as their common factor are called as $\underline {{\text{ }}}$
A) Co-primes
B) Twin prime
C) Composite
D) None of these

Answer 1

Hint:
In order to understand this concept in a better way, we need to understand the concept of prime numbers. By prime numbers we mean that it is a number which has only 2 factors, 1 and itself. Basically, the prime numbers can’t be divided by other numbers. Let us use this concept to answer this question.

Complete step by step solution:
It is known that the prime numbers are the numbers which have 1 and the number itself as its factors. All the numbers except these are known as composite numbers.
Moving on, we know that the twin prime numbers are pairs of prime numbers with a difference of 2 between them. A few examples are, 17 and 19.

Now, the co-primes can be defined as any two numbers having only 1 as their common factor. The converse for this also holds true. Also, it is important to note that the number in the pair of co-prime numbers, the numbers can be both prime and composite numbers.

Hence, the correct answer is co- primes, which is option (a).

Note:
It can be noted that twin prime numbers also have only common factor 1. But its converse does not hold true. Two numbers having only common factor 1 need not be twin prime. It can be said that twin primes are co primes but all the co primes can’t be twin primes. For example, 13 and 31 are twin primes.