which of following is not a prime number?
A)17
B)23
C)31
D)51
What do you think? First of all go on to Google and look up prime numbers. You'll get a way better understanding of them in a small amount of time. I'll give you one hint: 51 is a prime number because 3 and 17 are it's factors.
Luv4ever has a typo.
51 is NOT a prime number because 3 and 17 are it's factors.
To determine which of the following numbers is not a prime number, let's check each option one by one:
A) 17: To determine if 17 is a prime number, we need to check if it is divisible by any number other than 1 and itself. In this case, there are no numbers between 1 and 17 that divide evenly into 17, so it is a prime number.
B) 23: Like before, let's check if 23 is divisible by any number other than 1 and itself. Again, there are no numbers between 1 and 23 that divide evenly into 23, so it is a prime number.
C) 31: Continuing the same process, we check if 31 is divisible by any number other than 1 and itself. Once again, there are no numbers between 1 and 31 that divide evenly into 31, so it is a prime number.
D) 51: Now, let's check if 51 is divisible by any number other than 1 and itself. We find that 51 can be divided evenly by 3 and 17, which means it is not a prime number.
So, the number D) 51 is not a prime number.
To determine which of the given numbers is not a prime number, we need to understand the concept of prime numbers.
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. In other words, a prime number is only divisible by 1 and itself.
To identify a prime number, we can check if it has any divisors other than 1 and itself. If it does have additional divisors, then it is not a prime number.
Let's check each given number:
A) 17:
To determine if 17 is a prime number, we need to check if it has any divisors. We can do this by dividing it successively by natural numbers starting from 2. If we find any divisor, then it is not a prime number. In the case of 17, there are no divisors other than 1 and 17. Therefore, 17 is a prime number.
B) 23:
Again, we need to check if 23 has any divisors other than 1 and 23. After dividing it by natural numbers starting from 2, we find no divisors other than 1 and 23. Hence, 23 is a prime number.
C) 31:
Similar to the previous cases, we divide 31 by natural numbers starting from 2. Once again, we find no divisors other than 1 and 31. So, 31 is a prime number.
D) 51:
Now, let's check if 51 is a prime number. By dividing it by natural numbers starting from 2, we find that it is divisible by 3, as 51 รท 3 = 17. Thus, 51 has a divisor other than 1 and itself, which means it is not a prime number.
Therefore, the number that is not a prime number among the given options is D) 51.