Question

The prime number which comes just after 43 is:
A. 49
B. 45
C. 47
D. None of these

Answer 1

Hint: In the given option we can simply find factors of given number. When we get a number which has factor only 1 and number itself then we can say that is the correct answer because Prime numbers are that number which has factor only 1 and number itself.

Complete step-by-step answer:
As we know, the prime number has only two factors 1 and number itself. For example 43 has only two factors 1 and 43.
So we can find factors of given numbers.
Factor of 49 is given below:

So we can write 49 as
$49=7\times 7\times 1$
So 49 has a factor other than 1. It is not a prime number. This is not a correct answer.
Factor of 45 is given below:

So we can write 45 as
$45=5\times 3\times 3\times 1$
So 45 has a factor other than 1. It is not a prime number. This is not a correct answer.
Factor of 47 is given below

So from this we can say 47 have only 1 and 47 as a factor. So 47 is the next prime number just after 43.
Hence option C is correct.

Note: Composite numbers are numbers which have factors other than 1 and number itself. Composite numbers are not prime numbers.
We can also do this question as an approach of a composite number. In that case we can say which number is a composite number in given options is not a prime number.