Question

Successor of number “1” is
A. Prime number
B. Co-prime number
C. Composite number
D. Both A. and C.

Answer 1

Hint: Here we use the knowledge of the word successor that is the number that comes right next after the given number is called a successor of the given number. We check if the value of the successor is prime, co-prime or composite using their definitions.

Complete step-by-step answer:
* Prime number: A number that has its only factors as 1 and the number itself is called a prime number. Example: 2, 3, 5 etc.
* Co-prime number: Two numbers are said to be coprime if they have no common factor other than 1. Example: 2,3 are co-prime numbers
* Composite number: A number that is not a prime number is called a composite number. In other words, a composite number has other factors than 1 and the number itself. Example: 4, 9, 15 etc.
We are given the number as 1
We have to find the successor of the given number.
Since, we know the successor of a number is that number which comes directly after the number, or the number which succeeds the given number by value 1.
So, we add 1 to the given number to obtain the successor.
Successor of “1” is $$1+1=2$$
Therefore, 2 is the successor of 1.
We know $$2=2\times 1$$
Since, the number 2 has only two factors i.e. 1 and 2.
Therefore, 2 is a prime number.
We know that if a number is prime then it can’t be composite.
So option C does not satisfy.

So, option A is correct.

Note: Students many times make the mistake of selecting option B as co-prime number, but keep in mind for co-prime we always take a pair of two numbers. Here we have to check for one number only so that option cannot be right.