Question

Number of prime numbers between 50 to 60 is:
A. 1
B. 2
C. 3
D. 4

Answer 1

Hint:We are asked to find the prime numbers. So we will start from 50 one by one, and see if this is a prime number or not by writing all the factors of it and then we will check for 51 and so on upto 60 and eventually we will get our answer.

Complete step-by-step answer:
A prime number is one that have only two factors 1 and the number itself
Factors of 50 are 2, 5, 10 and 50, So this is not a prime number
Factors of 51 are 1, 3, 13 etc, so this is also not a prime number
Factors of 52 are 1, 2, 4, etc, so this is also not a prime number
Factors of 53 are 1 and 53 itself, therefore 53 is a prime number
Similarly, 54, 55, 56, 57, 58 are also not prime numbers
Factors of 59 are 1 and 59 itself, therefore it is a prime number
Factors of 60 are 1, 2, 3, 4 etc, so it is also not a prime number
So, we have only two prime numbers between 50 and 60.
∴ the correct option is ‘B’.

Note: This Question can be solved by using one more method by dividing the number by prime number, first divide it by 2,and see if you get a whole number. If you do, it can be a prime number. If you don’t, next try dividing it by prime numbers 3, 5, 7,11 and so on, always dividing by a prime number.